WIP
Convert Notification to an STI model and put everything under the Apns scope.
Make Apps responsible for constructing their own AppRunner.
Merge branch 'master' into gcm

Conflicts:
	lib/rapns/feedback.rb
Specs passing.
I took the 'super' approach in the end.
Acceptance test for generating migrations in a new app.
mv rspec/rapns spec/unit
Each app type has a corresponding runner.
WIP on a delivery acceptance test.
Introduce GCM models.
Shorten index name.
Diagnose git branch output on travis
Travis-CI doesn't checkout branches.
Passing on Rubinius now.
Merge branch 'master' into gcm

Conflicts:
	.gitignore
Little more work on GCM.
Fix specs.
WIP on gcm payload delivery.
Build status badge is for master only.