WIP: Sorting with a sorting func

Here is a proof of concept that simply applies a sorting function to our list box instead of throwing it away and recreating it from scratch. Also the initial population of the list could be faster now, compared to earlier... I would appreciate if somebody would test/time it.

Resorting big.kdbx with 1000 entries looked pretty smooth to me, in any case. How the heck, do we access the "Listbox" containing the entries when I have a page? There MUST be an easy way...