add coverage config

Author: thijstriemstra

.coveragerc

@@ -0,0 +1,7 @@
+# .coveragerc to control coverage.py
+[run]
+source = flickrapi
+omit =
+    setup.py
+    .tox/*
+    doc/*

tox.ini

@@ -8,6 +8,13 @@ commands =
     coverage run -m py.test -v --cov flickrapi -r wsx
 deps= .[test]
 
+[testenv:py36]
+commands =
+    python setup.py install
+    coverage run -m py.test --doctest-modules flickrapi tests -v -r wsx
+    coverage report
+deps= .[test]
+
 [testenv:qa]
 commands =
     flake8