Renaming Points.java to Pen.java since this is really what's doing the
drawing, and I intend to make this a pen that can draw different things
one day.

Creating a new class called Points.java (just to be confusing!), which is
actually a point object.  This will be used to start tracking touch
history for future use for acceleration and interpolation.

Modified MyGLSurfaceView and MyGLRenderer to start tracking a touchQueue
of touch events and passing it to the renderer.  Since the renderer is
still just drawing dots, it will just dequeue the last point event and
draw that for now.