Finished writing the SoundManager and documented all of its methods. Closed #59. Closed #5.
Refactored Graphics as a member of Game, to allow refresh-based rendering instead of looped rendering. This can enable huge performance boosts in such a game as the Whisperer in Darkness, where the scene stays the same for extended periods. Added a clearTransparent() method to Surface for convenience when using background images and ASCII captions.
Implemented mouse input for all 3 buttons (#57), as well as scroll wheel input, which remains untested. Still need to add buttons and text controls. Fixed a bug which could caused crashing in blitSurface() if the surface didn't fit.
Documented new Input methods.