Event handling, a couple of extra params and some classes

[MattReimer]

Hey there,

I love your keyboard. It's simple, semantically designed and does exactly what I need.... except for a few things.

I added some event handling for KeyPress events:

• onKeyClick: corresponds to onclick for any piano key
• onKeyDown: corresponds to onmousedown for any piano key
• onKeyUp: corresponds to onmouseup for any piano key

I also added a new parameter: nameOctaves which toggles the octave number in the key name.

Also there's a new namesMode called "both" that allows both sharp and flat to coexist.

Then I added some new classes so I can select octaves and also some convenience classes for white and black classes.

Don't feel you need to merge these but I thought they might be useful to give back.

Thanks for making such a great module!