Adopt NgModule

[StephenFluin]

Provide a FirebaseModule to be referred to by standard AppModules.

• Move FIREBASE_PROVIDERS into the FirebaseModule.

See this gist:
https://gist.github.com/StephenFluin/672b85faef772b8102457f4fe5dd02ce

cc: @wardbell @IgorMinar

[jeffbcross]

Note that this is blocked by Angular RC.5

[StephenFluin]

And in hindsight it should probably be AngularFireModule, not FirebaseModule.

[jeffbcross]

TODOs

• Get rid of typings in favor of @types
• Get rid of firebase3.d.ts (assuming version published to @types is good)
• Add new TS module with NgModule (don't include module in angularfire2.ts yet)
• Create a configuration interface for the NgModule that merges defaultFirebase and firebaseAuthConfig configuration objects.