Stop using extended method

I used `Ember.String.fmt` instead of `String#fmt`.
Because the latter may be undefined.
Fix failing test

This package couldn't be required from test.
Merge pull request #2235 from tricknotes/fix-failing-test

Fix failing test
Better HistoryLocation popstate handling - Fixes #2234
Fix 'rake test[built]' task
Merge pull request #2233 from tricknotes/stop-using-ext-method

Stop using extended method
Added Campfire notifications to Travis
Remove apparently inactive travis upload hook
Only notify Campfire when build status changes
Better warning for missing initializers - Fixes #1906