Update Travis build to use Anaconda
Travis updates and fixes
More travis fixes
Another travis attempt
Revert changes
Use PIL and Pillow
Refactor travis into 4 different builds
Fix activation error
Remove explicit mpl in build_versions.py
Make matplotlib an explicit requirement
Rearrange travis
Make pillow a hard requirement
Try again to make Pillow optional
Fix bash syntax error
Fix bash syntax error
Bump required cython version
More rearrangments
Remove mpl from build_versions, rearrange travis
Fix version check
Make matplotlib explicit again