Improving docstring + style/convention edits
Added some warnings for transparency.
PEP8 compliance!
One line.
Changed variable names so they actually make sense (followed Tony's
suggestion).
Hide experimental GSoC functions for 0.9 release
Temporarily remove censure keypoints example
Tiny formatting edits
FIX: Fix and improve Poisson random noise generator

The Poissson generator now works.

The improved Poisson generator now infers the bit depth of the image
after conversion to a floating point image, by analyzing the unique
values present and finding the next power of two. This value is then
used to scale the floating point image up, after which Poisson
noise is generated, and then image is then scaled back down.
ENH: More concise next-power-of-2 calculation
Fix numpy 1.8 bug
Split grey and binary erosion tests in two files
Fix overflow error
Reduce number of specializations
Remove unused import
Add support older numpy versions
Deprecate out parameter
ENH: Add optional `clip` kwarg, docs, & handling of signed inputs.
ENH: Tighten tests, all noise types now support signed I/O
TEST: fix mistake