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)
%%% should show a removed and b added
A b
R a
reverting...
saving current version of b as b.bak
forgetting b
undeleting a
%%% should show b unknown and a back to normal
? b
? b.bak
merging a
%%% should show foo-b
foo-b
%%% should show a removed and b added
A b
R a
? b.bak
reverting...
forgetting b
undeleting a
%%% should show b unknown and a marked modified (merged)
? b
? b.bak
%%% should show foo-b
foo-b