Configure the library for running on TravisCI

Removed dummy apps (we load the schema and models
necessary for testing). Added .travisci.yml with
a variety of environments to test. Added gemfiles
for rails 3, 4, and edge.
Don't allow failures anymore
Switch to RSpec
Isolate expectations
Fix query for Rails 3 where !=
Clean up expectations
Update README regarding testing

[ci skip]
Depend on ActiveRecord, not all of Rails