:bug: Fix force-adding a second Navigator keybind
:bug: Fix force-adding a second Navigator keybind

Seems to fix #41: Don't force-add(#12) a second Navigator keybind.You
cannot test for a String value in a TreeMap<String,TreeSet> - Now it
tests for a temporary TreeSet containing the String.

Signed-off-by: CisBetter <dad2387eadcc0b947b088e2f6260945a6e52ccf5@users.noreply.github.com>
CisBetter/Wurst-MC-1.10,Wurst-Imperium/Wurst-MC-1.10,CisBetter/Wurst-MC-1.10