Modifying the GemRB demo

[m7600]

Thanks to lynx, who fixed the transparency problem, the GemRB demo is getting a graphics update.

I'm starting to work on the fog of war, so that it doesn't look like black blocks. In the screenshot, I'm using the fog of war from Icewind Dale 2, but obviously that will not be the final one due to copyright reasons. Instead I'll make a new one from scratch, but I'm studying the IWD2 file in order to understand how to configure everything.