Split overworld model up by screen

Utils.py

@@ -743,6 +743,27 @@ def load_cached_yaml(path_list):
             return data
 
 
+class bidict(dict):
+    def __init__(self, *args, **kwargs):
+        super(bidict, self).__init__(*args, **kwargs)
+        self.inverse = {}
+        for key, value in self.items():
+            self.inverse.setdefault(value,[]).append(key) 
+
+    def __setitem__(self, key, value):
+        if key in self:
+            self.inverse[self[key]].remove(key) 
+        super(bidict, self).__setitem__(key, value)
+        self.inverse.setdefault(value,[]).append(key)        
+
+    def __delitem__(self, key):
+        value = self[key]
+        self.inverse.setdefault(value,[]).remove(key)
+        if value in self.inverse and not self.inverse[value]: 
+            del self.inverse[value]
+        super(bidict, self).__delitem__(key)
+
+
 if __name__ == '__main__':
     # make_new_base2current()
     # read_entrance_data(old_rom=sys.argv[1])