Merge branch 'polyobjthinkref' into 'next'

Fix polyobject thinker leak

See merge request KartKrew/Kart-Public!361

src/p_polyobj.c

@@ -150,6 +150,8 @@ FUNCINLINE static ATTRINLINE void PolyObj_AddThinker(thinker_t *th)
 	th->next = thinkercap.next;
 	th->prev = &thinkercap;
 	thinkercap.next = th;
+
+	th->references = 0; // init to 0 so they can be properly removed
 }
 
 //