Created a script that allows users to query our remaining geocoding credits.

Snu responds with a number of credits and an accompanying gif.  Lots of copy and pasting from the [socrata-cmd.coffee](https://github.com/socrata/snubot/blob/master/scripts/socrata-cmd.coffee) script.  Env vars will be sent separately for our private instance of snu.

Also updated .gitignore.