Adds pairing functions

First four commits are cleanup for how .bash_profile is organized.

Last commit is the important one: adds functions for setting up git env vars for "driver" related functions.  Usage is:

    me {username-or-alias}

E.g. all the following are the same:

    me bhaskell
    me ben
    me bh
    me benizi

Running `me` without arguments resets the username to `Pairing Station - short-hostname` and email address to `software@4moms.com`.

I added aliases for everyone as conflict-free as possible (first names where not duplicated, first-name last-initial where not conflicting).  You can add your own if you want (e.g. I added `benizi` for myself).  I used people's git-related email addresses where known.  (Everyone other than Dan, Justin, and Roger is just {username}@4moms.com)