.bash_prompt: Interpret escape sequences correctly in all cases

Closes #407.
Add command 'git-fuckit' courtesy of Chris Le

Alias to delete all the stupid shit you did last night. Gets you back to a clean repository.

http://www.chrisle.me/2012/12/git-fuck-it/
Merge branch 'master' of git://github.com/mathiasbynens/dotfiles

* 'master' of git://github.com/mathiasbynens/dotfiles:
  .bash_prompt: Interpret escape sequences correctly in all cases