Issue #638: Fixed C# TextureMap field types

[SpyderTL]

By default, Marshall.PtrToStructure converts char fields to 1 byte characters. Ushort fields are properly converted to 2 byte values.

This should fix Issue #638.

[deranen]

Why hasn't this been merged already?

[BOLL7708]

@deranen probably because the file is automatically generated so any changes to it would have to be done somewhere else, not in the actual file.

I bump into parameters and properties being wrong, floats that are doubles, ints that are chars etc. Feels like we could have a separate place just to report things in the C# header 😅