[Ohrrpgce] SVN: teeemcee/10411 Fix a couple crashes or null slice ptr debug errors that occur if a ps.c

[subversion at HamsterRepublic.com]

teeemcee
2018-06-01 18:14:32 -0700 (Fri, 01 Jun 2018)
264
Fix a couple crashes or null slice ptr debug errors that occur if a ps.cur=NULL in ThingBrowser

However there are more "IsAncestor null slice" errors that can occur if ps.cur
becomes NULL. And maybe that's a good thing, because it probably shouldn't ever
be NULL?
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U   wip/thingbrowser.bas