Update travis
Update travis

- Ruby 2.0, for consistency
- Set Rails patch version to 0.
- Remove deprecated Rails 4.0
- cache bundler

jgnatch/mountain_view,jgnatch/mountain_view,tombeynon/mountain_view,tombeynon/mountain_view,darioghilardi/pieces-engine,devnacho/mountain_view,tombeynon/mountain_view,jgnatch/mountain_view,darioghilardi/pieces-engine,devnacho/mountain_view,gazaston/mountain_view,darioghilardi/pieces-engine,gazaston/mountain_view,devnacho/mountain_view,gazaston/mountain_view