This makes demos render correctly on hiDPI displays,
while also demonstrating how to handle multiple resolutions.
The 3D in 2D demo now uses "3D No-Effects" for the 3D viewport,
which is faster to render. Thanks to this, 4× MSAA is now enabled
for a better result.
The background loading demo now uses mipmaps for better-looking images.
The material testers demo now samples mouse input in a
resolution-independent manner when panning.
Default clear colors were also changed in some projects for visual
consistency with the project's theme.
