Fixing a couple of bugs with the inputs
Trying to get up and down arrow movement to work.

I'm commiting this here to save my progress basically.  I'm going to revert all this and switch left and right arrow to shift tab and tab.

In the future I may come back to the arrow keys or numpad.
Handle tab and shift-tab myself.  Change the update event to be onBlur, like current datatable.

jQuery focus() automatically handles updating the scroll position of the table.
Removing unneeded things and debug code