Created CheckBoxes and RadialButtons and added them into the UiDemo
Created Color class to handle Color operations.
Modified volume setting in AudioManager
Modified documentation of Object.  No other changes there.
Added "set" command into Scene.  Currently only for background image or color.
Added in loop functionality in Song.
Added in restart function into Sound and made sure that subclasses inherit setVolume, restart and the variable timer.
Sound effects can now be played multiple times before being removed.
Modified SoundEffect.play to remove sound effect from AudioManager's sound array when it's over.