TabControl av mangja fan

This extension loads next N tabs relative to current active tab using a queue, for example next 10 tabs could be loaded 2 tabs at a time. When all 10 tabs are loaded, no more will be until the active tab changes.
Tabs that are not to be loaded are discarded, with an option to retain previous N number of tabs.
The number of tabs to be loaded at the same time is also configurable.
Another small feature if warming up the next tab.