Still has one `UI_ThemeColor` call, because drawing is happening in a DM
drawing callback which hasn't been converted yet.
Also has some old gl calls that are #ifdef'ed out.
This also changes active face drawing in UVs from stippled to a solid
color, which makes active faces much more visible, and also looks nicer.
The same should probably be done for active face drawing in the 3d view.
(has been discussed with merwin on IRC)
Part of T49043
Luna Rood
8add4cc900