closes#3153
- this is all about the validation engine
- add a option, `opts.model`, to use a passed-in model directly if needed
- handle validators that return an array of strings, array of objects, or both
- ajax util returns either an array of errors or a single concat'd string
- remove formatErrors function from the mixin and make it private
- allow validation options to be passed into `.save()` since ember-data doesn't take params on `.save()` anyway
- streamline control flow
Closes#2976, Closes#3017
- Move logic to signup controller
- Add ValidationEngine mixin to signup controller
- Add signup validator with code from clientold login view
- Add signin validator and integrate into signin controller
- Add validation to forgotten controller
- Switch to button action to support hitting enter in text field to submit
- Clear all notifications in notifications.closeAll
- Modify ValidationEngine.validate to not format errors based on option
- Update casper test for signin to wait for notification before trying
to do another signin
