Support for colour codes in label rendering

[mrzapp]

Should be formatted like {0.0,0.0,0.0}.

[MuNgLo]

maybe let it optionally take alpha to. Opening up for Unitys Color(RGBA). Have no idea how it fits in the rendering though.

[mrzapp]

I think it would make more sense to make it a multiplication of the already defined colour, and then just inherit the alpha from the widget. We could make it optional though.