Merge branch 'master' into astropy

This brings in all changes to trunk for PyFITS v3.3.0 between
8d2a54d3ef93e356a0d20a71924cff7ab8c87426 (SVN r2391) and
2ab1b36e8135beb37bcc53859985a52a82a0d880 (SVN r2796).  These are all the
changes from that period that were not also ported as bugfixes to the
3.2.x branch.

Conflicts:
	.coveragerc
	.travis.yml
	README.txt
	astropy/io/fits/card.py
	astropy/io/fits/column.py
	astropy/io/fits/core.py
	astropy/io/fits/fitsrec.py
	astropy/io/fits/hdu/base.py
	astropy/io/fits/hdu/compressed.py
	astropy/io/fits/header.py
	astropy/io/fits/tests/test_diff.py
	astropy/io/fits/tests/test_header.py
	astropy/io/fits/tests/test_image.py
	astropy/io/fits/tests/test_table.py
	astropy/io/fits/util.py
	docs/io/fits/appendix/header_transition.rst
	docs/io/fits/appendix/history.rst
	docs/io/fits/users_guide/users_headers.rst
	docs/io/fits/users_guide/users_tutorial.rst
	docs/io/fits/users_guide/users_verification.rst
	docs/source/conf.py
	docs/source/developers_guide/developers_guide.rst
	lib/pyfits/_release.py
	lib/pyfits/tests/test_checksum.py
	setup.cfg
	setup.py
	tox.ini

Conflicts:

	astropy/io/fits/__init__.py
	astropy/io/fits/card.py
	astropy/io/fits/column.py
	astropy/io/fits/convenience.py
	astropy/io/fits/core.py
	astropy/io/fits/diff.py
	astropy/io/fits/file.py
	astropy/io/fits/fitsrec.py
	astropy/io/fits/hdu/__init__.py
	astropy/io/fits/hdu/base.py
	astropy/io/fits/hdu/compressed.py
	astropy/io/fits/hdu/groups.py
	astropy/io/fits/hdu/hdulist.py
	astropy/io/fits/hdu/image.py
	astropy/io/fits/hdu/nonstandard.py
	astropy/io/fits/hdu/streaming.py
	astropy/io/fits/hdu/table.py
	astropy/io/fits/header.py
	astropy/io/fits/py3compat.py
	astropy/io/fits/scripts/fitscheck.py
	astropy/io/fits/scripts/fitsdiff.py
	astropy/io/fits/tests/test_checksum.py
	astropy/io/fits/tests/test_core.py
	astropy/io/fits/tests/test_diff.py
	astropy/io/fits/tests/test_division.py
	astropy/io/fits/tests/test_groups.py
	astropy/io/fits/tests/test_hdulist.py
	astropy/io/fits/tests/test_header.py
	astropy/io/fits/tests/test_image.py
	astropy/io/fits/tests/test_nonstandard.py
	astropy/io/fits/tests/test_structured.py
	astropy/io/fits/tests/test_table.py
	astropy/io/fits/tests/test_uint.py
	astropy/io/fits/tests/test_util.py
	astropy/io/fits/tests/util.py
	astropy/io/fits/util.py
	astropy/io/fits/verify.py
	docs/io/fits/api/hdus.rst
	docs/io/fits/usage/headers.rst
	docs/io/fits/usage/table.rst
	docs/io/fits/usage/unfamiliar.rst
	docs/io/fits/usage/verification.rst
	docs/io/fits/users_guide/users_tutorial.rst

astropy/io/fits/card.py

@@ -10,7 +10,7 @@
 from .verify import _Verify, _ErrList, VerifyError, VerifyWarning
 
 from . import conf
-from ...extern.six import string_types, integer_types, text_type
+from ...extern.six import string_types, integer_types, text_type, binary_type
 from ...extern.six.moves import xrange
 from ...utils import deprecated
 from ...utils.exceptions import AstropyUserWarning, AstropyDeprecationWarning
@@ -517,7 +517,8 @@ def keyword(self, keyword):
                     # also displayed
                     warnings.warn(
                         'Keyword name %r is greater than 8 characters or '
-                        'contains spaces; a HIERARCH card will be created.' %
+                        'contains characters not allowed by the FITS '
+                        'standard; a HIERARCH card will be created.' %
                         keyword, VerifyWarning)
             else:
                 raise ValueError('Illegal keyword name: %r.' % keyword)
@@ -564,24 +565,23 @@ def value(self, value):
         if oldvalue is None:
             oldvalue = ''
 
-        if not isinstance(value, (string_types, integer_types, float, complex,
-                                  bool, Undefined, np.floating, np.integer,
-                                  np.complexfloating, np.bool_)):
+        if not isinstance(value, string_types + integer_types +
+                                 (float, complex, bool, Undefined, np.floating,
+                                  np.integer, np.complexfloating, np.bool_)):
             raise ValueError('Illegal value: %r.' % value)
 
         if isinstance(value, float) and (np.isnan(value) or np.isinf(value)):
             raise ValueError(
                 "Floating point %r values are not allowed in FITS headers." %
                 value)
-
-        if isinstance(value, text_type):
+        elif isinstance(value, text_type):
             m = self._ascii_text_re.match(value)
             if not m:
                 raise ValueError(
                     'FITS header values must contain standard printable ASCII '
                     'characters; %r contains characters not representable in '
                     'ASCII or non-printable characters.' % value)
-        elif isinstance(value, bytes):
+        elif isinstance(value, binary_type):
             # Allow str, but only if they can be decoded to ASCII text; note
             # this is not even allowed on Python 3 since the `bytes` type is
             # not included in `six.string_types`.  Presently we simply don't
@@ -768,6 +768,27 @@ def image(self):
             self._image = self._format_image()
         return self._image
 
+    @property
+    def is_blank(self):
+        """
+        `True` if the card is completely blank--that is, it has no keyword,
+        value, or comment.  It appears in the header as 80 spaces.
+
+        Returns `False` otherwise.
+        """
+
+        if not self._verified:
+            # The card image has not been parsed yet; compare directly with the
+            # string representation of a blank card
+            return self._image == BLANK_CARD
+
+        # If the keyword, value, and comment are all empty (for self.value
+        # explicitly check that it is a string value, since a blank value is
+        # returned as '')
+        return (not self.keyword and
+                (isinstance(self.value, string_types) and not self.value) and
+                not self.comment)
+
     @property
     @deprecated('0.1', alternative='the `.image` attribute')
     def cardimage(self):
@@ -946,9 +967,6 @@ def _parse_keyword(self):
 
                 keyword_upper = keyword_upper[:val_ind_idx]
 
-            if keyword_upper != keyword:
-                self._modified = True
-
             return keyword_upper
         elif (keyword_upper == 'HIERARCH' and self._image[8] == ' ' and
               HIERARCH_VALUE_INDICATOR in self._image):
@@ -1316,18 +1334,24 @@ def _verify(self, option='warn'):
                 self._hierarch):
             pass
         else:
+            if self._image:
+                # PyFITS will auto-uppercase any standard keyword, so lowercase
+                # keywords can only occur if they came from the wild
+                keyword = self._split()[0]
+                if keyword != keyword.upper():
+                # Keyword should be uppercase unless it's a HIERARCH card
+                    errs.append(self.run_option(
+                        option,
+                        err_text='Card keyword %r is not upper case.' %
+                                  keyword,
+                        fix_text=fix_text,
+                        fix=self._fix_keyword))
+
             keyword = self.keyword
             if self.field_specifier:
                 keyword = keyword.split('.', 1)[0]
 
-            if keyword != keyword.upper():
-            # Keyword should be uppercase unless it's a HIERARCH card
-                errs.append(self.run_option(
-                    option,
-                    err_text='Card keyword %r is not upper case.' % keyword,
-                    fix_text=fix_text,
-                    fix=self._fix_keyword))
-            elif not self._keywd_FSC_RE.match(keyword):
+            if not self._keywd_FSC_RE.match(keyword):
                 errs.append(self.run_option(
                     option,
                     err_text='Illegal keyword name %s' % repr(keyword),
@@ -1351,7 +1375,7 @@ def _verify(self, option='warn'):
                 errs.append(self.run_option(
                     option,
                     err_text='Card %r is not FITS standard (invalid value '
-                             'string: %s).' % (self.keyword, valuecomment),
+                             'string: %r).' % (self.keyword, valuecomment),
                     fix_text=fix_text,
                     fix=self._fix_value))
 
@@ -1379,7 +1403,7 @@ def _itersubcards(self):
 
         ncards = len(self._image) // Card.length
 
-        for idx in xrange(0, Card.length * ncards, Card.length):
+        for idx in range(0, Card.length * ncards, Card.length):
             card = Card.fromstring(self._image[idx:idx + Card.length])
             if idx > 0 and card.keyword.upper() != 'CONTINUE':
                 raise VerifyError(