Fix Vip List sorting

Fixes Vip list sorting issues for both alphabetical sorting and
online/offline sorting. Fixes Issue #169
Tested in 8.61
Fixed Exit button not being created

It will now show/hide appropriately instead of not being created and
thus throwing errors.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	modules/game_viplist/viplist.lua
Minor Edits to UIMiniWindow

Allow for a double click on the Top Bar of a UIMiniWindow to function
the same as pessing the minimize/maximize button.
Fixed error in the NPC Trade system error message

item[1] was user data, so the error message now prints out the item
name.
Merge pull request #176 from Quintinon/master

Minor Tweaks to UI and Fixed an error in NPC Trade