Adding Presenter#hasView()
Better destroyChild() exceptions
Merge pull request #114 from square/py/destroy_errors

Better destroyChild() exceptions
Merge pull request #113 from square/py/hasView

Adding Presenter#hasView()
Support for Dagger 2

* Mortar is now agnostic of the dependency injection library.
* Backported Dagger1 support into a small module: dagger1support.
* Added a module for Dagger2 support: dagger2support.
* mortar-sample still uses Dagger1.
* mortar-helloworld now uses Dagger2.
* Removed support for runtime graph validation with Dagger1.