Fix icons (default location and in demos)
Created by: firefly2442
I was getting the following error in the project manager:
ERROR OPENING FILE: icon.png
By default, when creating a new project, the code was using icon.png
instead of res://icon.png
for the icon in the engine.cfg
file. This fixes that as well as adjusts the demos to either use that location if the demo has an icon or removes the icon if it doesn't have one.