Use a QList to manage the positions of the indexes in the views

NickListModel now has a QList holding the pointers so we have
an ordered list that stays consistent and don't have to do
funky stuff whenever the hash might reorder itself.
By having both we can maintain the fast lookup times of all of
the settings.
Fix a crash when a nick is renamed, we were calling this twice.
Fix a sorting bug where the orders were reversed

Both the status sorting and activity sorting were reversed
so the more active and higher status people would be on the
bottom.