Add new smh-theme, based on dst + RVM info

example prompt:
machine-name: ~/current/path [ruby-1.9.2-p290@foobar|master]
$                                                             [10:15:32]

An example can be seen here: https://skitch.com/stevenharman/fpuee/oh-my-zsh-prompt

(note: this exact formatting is dependent on my change in Pull Request 526 [https://github.com/robbyrussell/oh-my-zsh/pull/526 ].)