Fuck it, a bunch of fixes and changes.
Normalise the colour vertex attribute arrays, separate them from the other non-normalised pos, norm, uv.
Fixup the Image, Label3D types so now I have the mouse pointer - think I've also figured out how to fix the Skin and TextureFont drawing without rebuilding the VertexBuffer constantly.
Added a Transpose method to matrix4x4.
Added new material VtxColorMaterial because using the MultiMaterial for it was a confusing as hell.