Displays branch name for the svn segment
Displays branch name for the svn segment

SVN implements the branch notion at server level and the working copies don't
hold that information. This implementation gets the working copy root path and
extracts the basename, using it as a local branch name.

milkbikis/powerline-shell,b-ryan/powerline-shell,b-ryan/powerline-shell,banga/powerline-shell,banga/powerline-shell