(concatenated "UMSH" signature + datafile + anivfile)
This is pretty much 100% functional by now.
Hasn't been tested on platforms other than Linux yet, though.
Code definitely deserves some cleaning.
This was done mainly to reduce the amount of occurences of the word FTexture but it immediately helped detect two small and mostly harmless bugs that were found due to the stricter type checks.
Until now each subclass of FTexture had to implement the entire span generation itself, presumably so that a few classes can use simpler structures.
This does not work if a texture can have more than one pixel buffer as is needed for alpha textures.
Even though it means that some classes will allocate more data now, it's the only way to do it properly.
In addition this removes a significant amount of mostly redundant code from the texture classes.
- added alpha texture processing to all converted classes
As of now this is not active and not tested.
Note that as part of the conversion even those textures that were working as alphatextures will not look correct until the higher level code gets adjusted.
