Ignore output for develop branch
Check SelectionView's copyPasteElement's parent before removing
Setting null should apply to all cells in current selection; include code for future opt-in

Missed adding local var for selection
EditableCellSelectionBinding did not clean up mappings, would leak

* KO's arrayFirst returns the correct item, but [].splice expects an index, not an object,
  so items were never being removed from the global.
Explicitly null out DOM elements, after removing them