changed a few things to work with this version of graphics library
fixed so that reactive mouse x and y takes into account canvas position
simplified canvas and reactor because setting color, stroke, width doesn't need to be done separately
added music test
NEW WAY TO RENDER SOUND. fix tomorrow
fixed Mouse.scala so that coordinates are relative to top of page
added note, soundcomposite, parallelcomposite, and some default notes
removed commented out code
removed redundancies
updated demo
added methods to move up/down octaves
updated demo
notes about volume
fixed play timing
added more
added scalesnote to reactor
removed commented out code
added subscribeChanges to all reactors
fixed: note doesn't play immediately on page load. added: reactive types for listening to changes
added more to object Reactive