DO NOT USE THIS COMMIT - IT IS BROKEN

Refactored into a ParseWorkouts module and a Main class
Tried to write a getWorkout of type IO Workout but realized the
stuff I was doing with -XGADTs and the class constraint in the data wasn't
going to work
Heavy refactoring of Workout.hs

Got rid of class constraint in data declaration, eliminating need for -XGADTs
Added difficulty field to Workout to have more than one arg to Workout contructor
> This will be put in the common info later, but for now I will leave it there
WorkoutType is now data instead of a class.
Operations on WorkoutType will now have to be have full coverage for all types, instead
of each type implementing methods of the class.
This looks much neater and I think it will be much easier to code with
Set up ParseWorkouts and Main for actual parsing

For now, we will just output the workout the users enters to us
getWorkout holds a placeholder for now. We will implement it so that
it actually parses input and returns a Workout next