Update Vundle method calls
Ditch unused aliases

Add alias to unhitch
Move ps1_functions dir
Default to CRuby 2.1.2
Move hitch function
Move env exports to zshenv
Use pure as zsh prompt

Also move file sourcing for functions and aliases here, per advice of
the zshrc docs http://zsh.sourceforge.net/Intro/intro_3.html
Clean up install script

Also add zshenv and zshrc.