[Ohrrpgce] SVN: teeemcee/8689 bmp import: if there is an alpha channel, map fully transparent pixels t

[subversion at HamsterRepublic.com]

teeemcee
2017-04-27 20:40:10 -0700 (Thu, 27 Apr 2017)
286
bmp import: if there is an alpha channel, map fully transparent pixels to colour 0

Not very well tested. I made these changes mostly because I noticed
the RGBcolor(-1) default for transparency for quantize_surface
matching totally white pixels, when I didn't want it to match anything.
---
U   wip/allmodex.bas
U   wip/surface.bi
U   wip/surface.h