Most tools look for $VISUAL before $EDITOR, and we tend to want that
anyway. This allows people to customize the two, for example using GUI
vim for $VISUAL and normal vim for $EDITOR, or more extreme: `ex -v` for
$VISUAL and `ex` for $EDITOR.
* Use a regular alias to make `s` short for `rspec`
* Use an `rspec` shell function to route to zeus when appropriate
* Removes confusion from `s` working differently than `rspec`
* Removes need to use a special alias to get zeus working