Frictions: Split frictions list at reach split.

src/Model/Friction/Friction.py

@@ -213,6 +213,17 @@ class Friction(SQLSubModel):
 
         return new
 
+    def cloned_for(self, reach):
+        new = Friction(reach=reach, status=self._status)
+
+        new.reach = reach
+        new.begin_rk = self._begin_rk
+        new.end_rk = self._end_rk
+        new.begin_strickler = self._begin_strickler
+        new.end_strickler = self._begin_strickler
+
+        return new
+
     def must_be_saved(self):
         ssi = self._status.scenario_id