Fix gradle build files following android studio upgrade
Replaced Observer.onPillsLoaded event with Otto
Removed ITaskComplete interface from GetPillsTask

This now uses the Otto event bus for communication
Replaced Observer pill updated calls with Otto
Replaced Observer consumption added method with Otto
Replaced Observer consumption deleted methods with Otto event bus events
Replaced Observer feature purchase methods with Otto events
Replaced Consumption Info Dialog Observer methods with Otto events
Removed last of the Observer methods and the Observer class

All Observer methods and functionality has been replaced by Otto event bus
Updated crashlytics logging
Switched the StatsFragment to use ButterKnife for view injection
Replaced Logger with Timber