Colour palette and saveid

Added saveid.

Now using MSX 1.2 colour palette, based on how OpenMSX renders it – to be fair, I’m actually using a slightly bluish black (#10102C) instead of the original #000000 at colour 1.

I rounded box corners a bit instead of using squared boxes (not sure whether I’m gonna leave ’em like this, they’re looking like gravestones…) 🙄