Improved VCS reporting using python script

- Does not check git status, as it is too slow in large repos.
- Supports bazaar now as well.
- String is constructed by helper python script. It's now readable ;)
Fix prompt if not in repository

So now all results are reported by python script on one line, separated
with tab, and read simply reads two fields like that. The fields cannot
be empty, or read will skip them and shift everything.