Add fallback decorator for 3D images

We don't support images greater than 2D, so fall back on ndimage
Add 3d-fallback tests for binary functions
Add doctrings and comments in response to reviewers
Add tests for ndimage fallback for 3D white_tophat & black_tophat
Adjust hanging indentation whitespace in dict comprehension
Add whitespace following comma
Change binary morphology functions to output numpy.bool dtype
Remove repeated comments
Updated docstrings
Add test that the 2D results correspond to scipy's
Remove trailing whitespace
Fix calls to ndimage to use footprint argument
Change test of ndimage equivalence to use uint8 test image
Change ndimage test image to fit uint8 range
Merge pull request #1063 from nlsn/3d-fallback

Add fallback decorator for 3D images

When an image is 3D or higher, our morphology functions will now call out to scipy.