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)
#!/bin/sh
hg init
echo This is file a1 > a
hg add a
hg commit -m "commit #0" -d "1000000 0"
touch b
hg add b
rm b
hg commit -A -m"comment #1" -d "1000000 0"