added retrofit for the random joke fetching
implementing retrofit and rxjava.
adding in a ui specific model to be used with the screen only
Merge branch 'feature/implement_retrofit' of git://github.com/chenry/ChuckNorrisJokes into chenry-feature/implement_retrofit

Conflicts:
	app/build.gradle
	app/src/main/java/com/grjug/android/chucknorrisjokes/api/controller/ChuckNorrisApiController.java
	app/src/main/java/com/grjug/android/chucknorrisjokes/ui/RandomJokeActivity.java
Merge branch 'chenry-feature/implement_retrofit' into develop