Instead of LibGUI and WindowServer building their own copies of the drawing
and graphics code, let's it in a separate LibDraw library.
This avoids building the code twice, and will encourage better separation
of concerns. :^)
In order to repaint the GUI after the sound thread has produced some sweet
new waves, we post a CCustomEvent to the main thread's event loop and then
wake up that event loop via CEventLoop::wake().
This frees up the main thread to draw the GUI. The secondary thread uses
a pipe to trick the main thread's event loop to break out of select() and
update() the PianoWidget. :^)
The idea here is to implement a simple synhesizer that allows you to play
music with your keyboard. :^)
It's a huge hack currently but we can improve upon this.
