[Ohrrpgce] SVN: teeemcee/12098 reload: fix many errors in the error checking for AddChild/SetRootNode/A

[subversion at HamsterRepublic.com]

teeemcee
2020-12-02 20:02:16 -0800 (Wed, 02 Dec 2020)
674
reload: fix many errors in the error checking for AddChild/SetRootNode/AddSiblingBefore/After

Most of these functions didn't ensure that the document root can't have a
parent, didn't ensure they weren't creating a loop in the slice tree, and didn't
check for various null ptrs.

AddSiblingBefore/After checked they weren't moving a slice to a different point
in the same family, which is actually fine.  Removing this fixes a bug in the
hero battle menu editor: insert-after didn't work.

SetRootNode had some pointless verifyNodeLineage calls.

I deleted the inscrutable verifyNodeLineage and verifyNodeSiblings functions,
thank goodness. Just use NodeHasAncestor instead.
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U   wip/heroedit.rbas
U   wip/reload.bas