[Ohrrpgce] SVN: teeemcee/11904 Ensure a=255 in master palette; fixes not detecting when image palette m

[subversion at HamsterRepublic.com]

teeemcee
2020-07-18 19:10:44 -0700 (Sat, 18 Jul 2020)
191
Ensure a=255 in master palette; fixes not detecting when image palette matches master palette when importing backdrops.

Also, load alpha values from png palettes, but ignore them everywhere.
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U   wip/allmodex.bas
U   wip/blit.c
U   wip/common.rbas
U   wip/drawing.bas
U   wip/plotscr.hsd
U   wip/subs4.bas