stablesort: write a flat version of the algorithm This new version never needs to iterate over the full repository even when merge are encountered. Having the algorithm flat also prepare caching works since the iteration sequence can we expressed with a couple of flat loop.

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