Workout Summary and  Workout Detail

Description
==========  

+ Parse and store workout and result data in `Workout` class. (Note: `Result` inner class is not used right now. I might delete it because it seems like we won't need it. Ignore for now.)
+ Workout Summary is now live; pulls from the TrainerAPI.
+ Added Workout Detail. It is also live except for graphs and icons/images.

__Adds__  

+ WorkoutDetailActivity.java - displays the details of the selected workout. the selected workout is passed via an intent extra called `workout_id`
+ Workout.java - stores the data for a workout in a map. each `TraineeItem` has an `ArrayList<Workout>` and a `HashMap<String,Workout>`, which maps from workout ID to the workout.
+ workout_complete_summary.xml - layout used for each completed workout in WorkoutHistoryActivity
+ workout_incomplete_summary.xml - layout used for each future/missed (incomplete) workout in WorkoutHistoryActivity
+ activity_workout_completed.xml - layout used in WorkoutDetailActivity
  + still need a layout to display an incomplete workout in detail view

__Changes__  

+ All workout names and values are pulled from the TrainerAPI, except images and graphs (still static since we haven't figured it out yet)
+ Trainee images in Stats (TraineeDetail) are now dynamically displayed.
+ WorkoutHistoryActivity - deleted all static images, and dynamically replaced them with workout views, either workout_incomplete_summary.xml or workout_complete_summary.xml, using `LayoutInflator`
+ APIHandler - all methods are now static.
+ The current trainee ID is set and stored in SharedPreferences