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

hg init
echo 123 > a
hg add a
hg commit -m "first" -d "0 0" a
mkdir sub
echo 321 > sub/b
hg add sub/b
hg commit -m "second" -d "0 0" sub/b
cat sub/b
hg co 0
cat sub/b
ls sub

true