Use RoboGuice instead of the current manual Guice code

[rdsubhas]

RoboGuice is a framework that brings the simplicity and ease of Dependency Injection to Android, using Google's own Guice library.

We currently have our own Guice code, and we manually added Guice. Instead of that, we want to add RoboGuice in the proper way as discussed in the Android bootcamp.

Tasks:

• Remove "Injector" from the RapidFtrApplication, and instead use RoboApplication
• Make the activities extend RoboActivity. Most activities inherit from RapidFtrActivity - so you can also make RapidFtrActivity extend RoboActivity.
• Add "roboguice.xml" and configure utils/ApplicationInjector as a module
• Wherever we're manually calling "inject(someclass)", use this style instead

[JamesMura]

Taking this on

[JamesMura]

https://github.com/rapidftr/RapidFTR---Android/pull/156