merge with upstream master

helix/helpers/nodequadtree.py

@@ -130,8 +130,14 @@ class NodeQuadTree():
                 self.nodeList = toKeep
 
     # Return a list of all possible nodes that can be near this point
-    def retrieve(self, nearPoint):
-        retNodes = list(self.nodeList)
+    # Optimization `only_quads_related = True`:
+    # Avoid replicate a large self.nodeList. Get only the other elements.
+    # Call this in complement of `self.nodeList`
+    def retrieve(self, nearPoint, only_quads_related=False):
+        if only_quads_related:
+            retNodes = []
+        else:
+            retNodes = self.nodeList[:] # = list(self.nodeList)
 
         if self.quads[0] is not None:
             index = self.getIndex(nearPoint)