[Ohrrpgce] SVN: teeemcee/9405 sliceedit: avoid error message when editing a lookup codename while live

[subversion at HamsterRepublic.com]

teeemcee
2017-09-19 07:51:02 -0700 (Tue, 19 Sep 2017)
168
sliceedit: avoid error message when editing a lookup codename while live prviewing
Did this by simply not writing slicelookup.txt. Added can_write_to_workingdir global.
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U   wip/lumpfile.bas
U   wip/lumpfile.bi
U   wip/sliceedit.bas
U   wip/yetmore2.bas