rewrite revert command. fix issues 93, 123, 147.
new version does these things:
- saves backup copies of modified files (issue 147)
- prints output like other commands, and errors when files not found
(issue 123)
- marks files added/removed (issue 93)
syntax: glob
*.elc
*.orig
*.rej
*~
*.so
*.pyc
*.swp
*.prof
tests/*.err
build
dist
doc/*.[0-9]
doc/*.[0-9].gendoc.txt
doc/*.[0-9].{x,ht}ml
MANIFEST
patches
mercurial/__version__.py
syntax: regexp
^\.pc/