Delete .icns file, and in its place, use a .iconset for the application

icons.  Add the 512x512@2x icon.  Update Makefile to build the .icns file
by using iconutil.  Bump CFBundleVersion.

Author: xrme

Info.plist

@@ -21,7 +21,7 @@
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
-	<string>70</string>
+	<string>71</string>
 	<key>LSApplicationCategoryType</key>
 	<string>public.app-category.lifestyle</string>
 	<key>LSMinimumSystemVersion</key>

Makefile

@@ -9,14 +9,15 @@ BINARY="$(CONTENTS)/MacOS/Picture Window"
 NIBS=MainMenu.nib dpf-preferences.nib help.nib
 
 build:  nibs 
+	iconutil -c icns app.iconset
 	mkdir -p $(RESOURCES)
 	cp $(NIBS) $(RESOURCES)
 	$(CCL) --no-init --load build.lisp
 
 nibs: $(NIBS)
 
 clean:
-	rm -f $(NIBS)
+	rm -f $(NIBS) app.icns
 
 dist-clean: clean
 	rm -rf build