Added a PCM WaveForm Generator Demo

This was a very difficult task to accomplish using JS alone. 44,100 samples
per second is apparently to taxing for the WebKit/JSTools (JSE). No matter.

The demo exemplifies the feasibility of this software system by compiling a shared library written in C on the fly, executes the desired shared operations, and returns control to the user. To run this example issue the following command from the project directory:

example/pcm/wavegen | aplay -f s16_le -r 44100

Added: example/pcm/waveform.c
Added: example/pcm/wavegen