Update travis build configuration
 * Add ruby 2.0.0 and 2.1.0 to travis builds
 * remove obsolete rbx-19mode
 * add rbx-2.1 and rbx-2.2 as allowed failures (rbx setup fails on travis)
 * ensure travis doesn't append '-- deployment' to bundle install
Merge pull request #12 from spovich/master

Update travis build configuration