push: add extra warning about pushing to old server Pushing using old method is slow and racy. We adds warning to point this to the user. We also add inline comment to clarify the function purpose.

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