Add Game Loop

[gbroques]

We need to add the game loop.

Here's some pseudo code of what it might look like:

current_position = 1
while song.is_not_finished(current_position):
    note_sequence = song.get_sequence(current_position)
    play_sequence(note_sequence)
    wait_for_player_to_match_sequence()
    wait_for_cozmo_to_match_sequence()
    current_position += 1

UPDATE: Issue #13 is responsible for completing 1 iteration of the loop. That should hopefully make this issue trivial.

[gbroques]

There's a lot of interactions that need to happen to make the game engaging, but aren't necessary for the game's functionality.

Let's worry about the interactions later, and get the core game mechanics finished first.