most transactions now properly set selection after modifying content, for Do, Undo, Redo.
lots of cleanup and minor bug fixes.
git-svn-id: svn://10.0.0.236/trunk@21466 18797224-902f-48f8-a5cc-f745e15eee43
* added DeleteSelection to editor. Doesn't work very well yet because selection is giving me random offsets into text content.
* lots of work in the various transactions.
git-svn-id: svn://10.0.0.236/trunk@18122 18797224-902f-48f8-a5cc-f745e15eee43