Add:core:Detect motorway interchanges

Signed-off-by: mvglasow <michael -at- vonglasow.com>
Refactoring:core:make sense of local variables in maneuver_required2()

Signed-off-by: mvglasow <michael -at- vonglasow.com>
Add:core:Complete handling of merge_or_exit

Signed-off-by: mvglasow <michael -at- vonglasow.com>