Added tag for '(Untracked File)' next to 'branch head' info

For files in a git directory that's untracked, adding an '(UNTRACKED FILE)' tag next to the branch head info.

Result should look something like this:
http://imgur.com/Lq1m9tg

Feel free to replace '(UNTRACKED FILE)" with something more aesthetically pleasing / takes up less space