Update JBallDroppings.pde

"Port" to Processing 2.x.
- Remove all external dependencies (Sonia, jsyn, .aiff file), replacing with generated sound via "official" Processing library Minim (http://code.compartmental.net/tools/minim). These changes are almost exclusively in `initSound` and `playSound`.
- Add one file (BumpyInstrument.pde) - an Instrument for Minim (tweaked from the example at http://code.compartmental.net/minim/oscil_field_amplitude.html), making it easier to change the sound (or replace it entirely).
- Refactor 'Line' class into 'BounceLine' due to conflict with Minim.
- Default to P3D renderer. Seems to perform slightly better than P2D on my machine.
- Remove all commented code.
- Remove a few no-longer-used variables.
- Reformat (Hi, I'm OCD).
- Set the default "emitter" position to top-middle. I like it there :)