With CHANF_OVERLAP this isn't needed anymore - any sound started on CHAN_AUTO can actually play on this channel with overlap implicitly allowed.
This has the added advantage that these sounds can be reliably accessed with other function by using CHAN_AUTO.
- screen bevel now enlarges also when screenblocks <= 11
- make intermission and status bar scaling game-specific in the config
- add scaling customization for classic ui flat scaling
- make screen border flat scale up
- inter_classic_scaling now defaults to true
- fixed: last commit I accidentally left hardcoded testing values and did not change them back to check for the texture's original size
- implement cvar 'inter_classic_scaling' to render the intermission flat as if it were 320x200
* handle brightmaps in the main shader instead of keeping separate instances around.
* added detail and glow layers from Raze.
* fixed material setup which could not guarantee that everything was initialized correctly.
* for warped textures, warp all layers. With this brightmaps finally work on warped textures.
Note: Vulkan reports a "device lost" error with this which still needs to be investigated.
