Incorrect TMS9918 color table mask

[spth]

In mode 2, Meka uses the mask derived from the lower bits of the pattern table register both for the pattern table and the color table. But AFAIK for the TMS99* the color table uses a separate mask derived from the lower bits of the color table register.
I guess this could be fixed by having a separate mask for the color table in Display_Background_2 in https://github.com/ocornut/meka/blob/master/meka/srcs/video_m2.c
I do not know how the SMS1 VDP behaves in that respect.

Philipp