make all commands be repo-wide by default - refactor code in commands.py so that: if no pattern is given, the command will be repo-wide else it will work on the working dir - update the doc - fix the tests

#!/bin/sh

mkdir t
cd t
hg init
echo a > a
hg add a
hg commit -m "test" -d "0 0"
hg verify
hg parents
hg status
hg undo
hg verify
hg parents
hg status