evolve: rename handlenotrouble to _handlenotrouble and add doc As suggested by Pierre-Yves on his comments on f113636997660b807c36cf1d0a06b76d53ada1a4 we make it clear that this function is private and explain what it does.

syntax: re
/figures/[^/]+\.png$
^docs/build/
^docs/html/
^html/
\.pyc$
~$
\.swp$
\.orig$
\.rej$
\.err$
^tests/easy_run.sh$
^build/
^MANIFEST$
^docs/tutorials/.*\.rst$
\.ico$