Added text, audio, workout buttons to TraineeDetail, with token

Description  
==========

+ Added buttons to `TraineeDetailFragment` to launch text, audio, and workout activities.
  + Text button launches `MessageActivity`  

+ The trainer's login token is now passed between these activities. To retrieve:
  + In the `onCreate` method:
    + `Intent intent = getIntent();` // Note: If you are in a Fragment and not an Activity, use `getActivity().getIntent();`
    + `token = intent.getStringExtra("token");`   
 
+ Added some layout/containers/views to `fragment_trainee_detail`, according to the layout in Prototype 3.0.