added GetWorkoutInstanceID(), GetWorkoutHistory(). Changed AddSet() to include WorkoutInstanceID
added GetWorkoutInstanceID(), GetWorkoutHistory(), GetWorkoutVolume(). Changed AddSet() to include WorkoutInstanceID
added GetWorkoutVolume()
removed pointless comments
added currWorkoutInstanceID
updated AddSet(), workoutHistoryList(), startWorkoutButton_clicked()
changed exercise_set_log to include workout_instance_id