Takes a target virtualenv directory as sole argument, and exports $VIRTUAL_ENV
and $PATH
in subshell.
Simple alternative to the virtualenvwrapper workon
workflow.
You'll want to have your prompt set via a login .rc of some form. eg: https://github.com/zoeglynn/dotfiles/blob/8c627e46a61f547fe6965e5a6b0b1dbec64ecdc1/.bashrc