[Mac] Create AddOns directory to open if needed
Re-enable new planets

Allow loading of cube map data, cube maps now work correctly in non-shader mode.
Cube map support for new planets
Fix last two cherry-picked commits so that they compile again

The whole NEW_PLANETS bit requires a fairly decent graphics card, so it's basically turned off unless the detail level is at "extras".
Draw atmosphere, and generate it if texture was not generated.
Add console.maximumDetailLevel
Bump tests for material suite
Try new atmosphere
Make NEW_ATMOSPHERE clouds a bit more visible
Fix super initialization in OOPixMapTextureLoader

This may affect planet rendering, but I couldn't see any differences.
Implement "extra shrink" texture flag

In reduced detail mode only, this limits texture sizes to 256 px per edge,
and shrinks textures that started at 256 px to 128 px.
OpenAL seems to be working without problems, so remove the old SDL sound files

Similar cleanup needed on Mac.
Enable multitexture light maps in minimum detail mode

Uses "extra shrink" mode to keep light maps small.
Reorganize multitexture code to avoid redundant work

Before, emission and illumination maps would be loaded synchronously
in order to determine the cache key of the combined texture.
Remove Core Audio sound implementation
Remove makefile references to old SDL sound code
Remove alloy from demoships parade.
Bump binary resources and tests/
Regenerate planet texture if detail level changed
Forward declare a method for gcc