Renamed shanty in comment to boxci.

I did this for consistency so that there isn't confusion in the future.
Rename require shanty to require boxci in Rakefile.

I did this so that the "rake console" command would work properly again.
Rename puppet fact "role" from "shanty" to "boxci".

I did this so that the naming is consistent across the board.
Rename openstack node names to boxci. Fixes #33.

I did this because I want it to be clear what the nodes are managed by when
looking at the nodes and people will gradually start to dissassociate the old
name "shanty" with the project and start associating "boxci" so it will over
time eliminate confusion.