Pinned tab is a locked tab with temporarily changeable address. It resets to pinned address on tab reactivation.
This feature is inspired by Total Commander's Lock tab with changeable address.
Requested by several users. See krusader-users mailing list: https://groups.google.com/forum/#!topic/krusader-devel/wp05sopv1SU
I've simplified occasional parts of code and also added "lock" and "pin" icons to the tab context menu actions.