Cleaned up the row and column adders for smoother scrolling, fewer crashes.
Made code more DRY with a canonical cell object with atteched events for repeated cloning.
Fixed the F2-to-edit-cell functionality.
Fixed bug in Colum titler to make correct titles in 27-702 Range, expanded (theoretical) column range to 18278.
Removed an unused global.
UI Tweaks
Major refactoring:
Wrapped everything in a handy global object called "app".
Optimized a bit so that the spinner looks a little cleaner (still pretty rocky).
Pruned out code that was intended to be used, but not actually.  Will reintegrate later.