VertexLayout.HasAttribute: wrong comparasion

[PowerStateFailure]

There should be
return ptr->Attributes[(int)attribute] != UInt16.MaxValue;
instead of
return ptr->Attributes[(int)attribute] != 0xFF;

See https://github.com/bkaradzic/bgfx/blob/master/src/vertexdecl.cpp#L162

[Michael Popoloski]

Nice catch. I'll get that fixed up when I get a chance.