Dev/jpsnyder/speaker

Created an interface for using pygame as well as controlling volume, beeps, tones made from sine waves, and text to speech. 

Closes #7 
As Sound() and Music() are very similar, and pygame.mixer.Sound() and pygame.mixer.music have essentially the same interfaces, I would take advantage of that and not rewrite functions for the Music class.  Specifically, I would remove the play(), stop(), set_volume() and get_volume() functions.  That requires removing currently_playing_file as well.

That means that the functions would be:

Music() - return music object without loading anything
Music(filename) - return music object with filename load()ed
Note: for either case above, set self.sound = pygame.mixer.music

music.queue() - leave as is
music.pause() leave as is
music.unpause() add as call to pygame.mixer.music.unpause()