Git and Mercurial branchname in PS1

If you’re working with version control systems like Mercurial, Git or SVN (if you must) and there with multiple branches, it’s sometimes really hard to keep track of what branch you’re currently in. There are a couple of utilities out there that help you integrate that information in your shell’s prompt, but most of them are limited to just one versioning system. Gred Ward’s vcprompt is different in this regard since it supports Git, Mercurial and some other system I don’t want to name here ;-) And it is really fast :D