evolve: move the logic of continuation handling of `hg evolve` in own fn The function which defines the evolve command is pretty big with all the logic messed up there. It's better to have individual functions for individual uses. The movement of code will help in adding more logic to continue part in clean way. Moreover for implementing `hg continue`, we need all continuation handling in their own functions, so it will help there too.

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

^docs/training/graphs/
^docs/training/html/
^docs/training/index.html
^docs/training/graphviz-images/
^docs/training/img/
^docs/training/output/
^docs/training/pandocfilters/