Remove ree and 1.9.2 from testing, add rbx instead
Use ActiveSupport::JSON for dumping json in render

This relieves us of any extra work that comes with handling JSON engines, etc.
State rbx mode explicitely
Merge pull request #1022 from padrino/be-nicer-to-travis

Remove ree and 1.9.2 from testing, add rbx instead
Merge pull request #1025 from padrino/active-support-json

Use ActiveSupport::JSON for dumping json in render