pep8 fix e225

Signed-off-by: Thomas Hisch <t.hisch@gmail.com>
e227 e228

Signed-off-by: Thomas Hisch <t.hisch@gmail.com>
colorconv from scikit image
Modify colorconv to use local dtype and numpy
Use local colorconv rather than scikit-image
Add scikit image license
Remove Lena examples
made idle_event() in backend_bases.py return True
Merge pull request #3769 from ahaldane/master

BUG/API : made idle_event() in backend_bases.py return True
Merge pull request #3771 from thisch/pep8fix_e225_e227_e228

PEP8 : [examples] fix pep8 error classes e225, e227 and e228
Merge pull request #3737 from jenshnielsen/rgb2lab_minimal

Rgb2lab minimal
use argparse to parse input in make.py
Exclude doc files not in the toc tree
Add option to treat sphinx warnings as errors
treat warnings as errors

When building docs with Travis