This adds support for ForkLift 3, which uses a different
application id and also uses a popover instead of a sheet for
entering the directory to go to.
This also improves the handling of different versions of ForkLift,
by first choosing any currently running instance, and if none is
running starting the newest available version.
Fixes#6565.
The ForkLift plugin now supports ForkLift 2 as well as ForkLift 1.
If ForkLift is not running it also waits for it to be running before
trying to switch to the specified directory
