(Partial) Decoding png_xb1/bmp_xb1 Support

[InvoxiPlayGames]

• Mipmaps are embedded in the DDS texture itself. The 8 bytes of unknown data in the mipmap data in the header looks to be related to this feature + the zlib compression mentioned below.
• Some time around Rivals they started compressing textures with zlib.
• Textures are tiled/swizzled - assuming it's the same, or at the very least similar to 360.

Currently the swizzling seems to be broken so I'm pushing this as a draft (and I don't know if this breaks decoding of version 6 or other textures). I just YOLO'd it with the framebuffer swizzling code from libxenon for testing and it made the result look more recognisable.