Adding README
Early refactor work for audio playback fixes

So far the major changes have been around the loop/instrument models. It turns out, we need to create a new AudioBufferSourceNode every time we want to play a sound. It can only play once. This refactors things so that the InstrumentModel stores its own buffer, but the audio service handles playback by creating new sources when play() is called.

I'm also renaming the little buttons to beat buttons but that's next.
Beats in place

Using BeatCollection, BeatModel, etc. A beat is essentially a button on screen. And the number that shows depends on the total beats per song
activateNext() fixed

This now activates the next item based on an event broadcast. That's still flimsy because the tracks could somehow come out of sync. Anchorning the playback on a BeatCollection index would be better.
Adds as watcher for bpm

There's also a newly found bug where the last instrument added always plays the wrong sound (presumably the first instrument's sound).
Sounds playing merrily now :)
Merge pull request #3 from brandonaaskov/loop-refactor

Loop Refactor