obscache: distinct 'clear' and 'reset' We make a difference between basic invalidatiton (or lack of loading) and 'reset' (current cache data are invalid). We can now ensure a non-None key when we start the update. This will allow us to "update" the existing key instead of recomputing one from scratch. This is more efficient and less racy.

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