Typo fix and some work making things a little more generic

Here is the typo fix for fabfile.py.

I also broke the stuff that switches you over to zsh out into a separate fab command (and stuck it in setup_all). That should make it a little more obvious that setup_all will change your shell, as well as make it easier to disable.

My text editor (sublime text) automatically trims trailing spaces upon every save, so that happened too.

I haven't actually managed to get a complete install working yet, so I can't say I didn't introduce any bugs. It certainly loads with `fab`, but there are a lot of assumptions about pre-existing folder structure that must be met before the install will work properly, and I'm still puzzling them out.