evolve: skip unstable changesets with multiple successorssets We were previously crashing when encountering them, but we want to be able to solve the other solvable troubles instead of stopping right there.

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