Update .travis.yml to downgrade rubygems

Squashed commit of the following:

commit b1c0bd5f0394a9339b1d0394a7f39e5c6bac3826
Author: Luke Baker <lukebaker@gmail.com>
Date:   Mon Mar 18 15:13:49 2013 -0400

    remove debugging travis.yml

commit df35180b4a1181248dee5a8578d677566f475ea3
Author: Luke Baker <lukebaker@gmail.com>
Date:   Mon Mar 18 15:05:47 2013 -0400

    more travis.ci testing

commit 3b47ee9f1db531127f20e4436b1c14ec0fd98116
Author: Luke Baker <lukebaker@gmail.com>
Date:   Mon Mar 18 14:56:36 2013 -0400

    more travis testing

commit 925d3d4a912a90290f90155d07bf6abd9ffd5339
Author: Luke Baker <lukebaker@gmail.com>
Date:   Mon Mar 18 14:40:06 2013 -0400

    add bundle exec to rake command