demo on Gambas library

[Jack <jscops@xxxxxxxxxx>]

Hello,
I was on this forum about ten years ago :-)
At the time I published a series of demos using the SDL component, which 
has now been removed from Gambas.
So I'm modifying some of these programs to make them compatible with the 
SDL2 component.
I've put two of them in the Gambas library: Cube and UGD.

--
Jacky Tripoteau