Added GLES 1.x spinning cube-rendering code to eglbringuptest
The coordinate, color and index data are uploaded to server-side
buffers by the CGLES1Cube::KhrSetup function. CGLES1Cube::KhrPaint
just sets the view matrix and issues a draw command.
Which demo to display can be selected by passing its name on the
command line, e.g.
eglbringuptest vgline
eglbringuptest gles1cube
If no name is provided, the application defaults to vgline.