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
port:4:export
port:4:vaportight
port:4:import/export
FIXME: history is wrong here
port:1:1:-:eggs:import
port:1:2:+:eggs:vaportight
port:1:3:+:eggs:import/export
port:0:2:+:spam:export
port:0:1:+:spam:import
port:4:import/export