Add tifffile support for MultiImage
Update multi_image test and install tifffile for travis.
Fix implementation errors
Add tifffile support for MultiImage
Update multi_image test and install tifffile for travis.
Fix implementation errors
Cleanup
Add animated gif, a test for it, and tests without conserve_memory.

Add animated gif, and a test for it, plus tests without conserve_memory

Add the gif file
Fix problems from rebase.
Add a comment about reading in order
Use pil_to_ndarray to load PIL images
Fix implementation of pil_to_ndarray in MultiImage
Allow multiple frames in PIL data in imread
Allow PIL imread to read multiple images
Add a note about sequential access.
Change MultiImage to use new imread.
Avoid circular import
Fix failing tests
Finish merging multiimage capability into collections
Pep8 cleanup