[Ohrrpgce] SVN: teeemcee/12598 Remove vestiges of plank slice collection groups. No longer used

[subversion at HamsterRepublic.com]

teeemcee
2021-10-29 22:07:02 -0700 (Fri, 29 Oct 2021)
148
Remove vestiges of plank slice collection groups. No longer used

Well there is one more, in the name SL_PLANK_HOLDER, which I have in my sights
too
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U   wip/menustuf.rbas
U   wip/plankmenu.bas
U   wip/plankmenu.bi
U   wip/slices.bas
U   wip/slices.bi