Initial commit of adapthist modifications.
Tests pass and example works on build.
Added Notes to the docstring.
Pep8 fixes.
Replaced generic ACM license with the Graphics Gems IV license.
Improved support for color images using lab transform.
Passed all tests with full coverage, PEP8 and Pylint performed.
ENH: Allow imread to read URLs
Fix handling of temporary file.

Opening an already-opened file was unsafe. Close the file, then manually delete it.
ENH: Add test and support for reading file URLs
STY: Fix confusing use of context-manager.
Translated clahe C code to python, added to list of contributors.
Removed sys.path hack in test, fixed spelling of import in __init__.py
Add example for hough_peaks function
FEAT - combined API from is_local_maximum() into peak_local_max()

is_local_maximum() is a wrapper function for peak_local_max()
is_local_maximum() runs much faster (~20% of prior runtime, nearly = to peak_local_max())
All tests in .feature and .morphology subpackages pass as written with these changes.

Todo:
  * Fully document API
  * remove commented-out old algorithm in is_local_maximum()
  * add new tests for full coverage of new, more complex peak_local_max()
FEAT - Unified peak finder backend

Detailed changelist:
  * Fully documented new API for peak_local_max()
  * Removed commented-out old code for is_local_maximum()
  * Added "See also" and "Notes" to is_local_maximum() redirecting to peak_local_max()
BUG - Fixed a bug where, when `indices` = False, output was not Boolean.
BUG - Fixed a bug where the image was not properly masked for each unique label.
BUG - Now parsing all unique labels != 0 properly, and set threshold_rel=0 in is_local_maximum() wrapper.
BUG - Dtype conversion to Boolean in a new code path not included in current tests.