Add ability to re-arrange TODO list items

[isaadoug]

Currently I cannot re-arrange TODO list items. For example, if I had a TODO list of 10 items I wanted to insert a new item after the 3rd item. I'd have to manually create 7 new items and move items 4-10 (base-1 index) down one slot in the list in order to insert the item at that middle position. This is not ideal.