Fixes a memory leak where each spines' path was a view of the spine path of the previous run.

Author: mdboom

lib/matplotlib/spines.py

@@ -247,7 +247,7 @@ def _adjust_location(self):
         else:
             low,high = self._bounds
 
-        v1 = self._path.vertices[:] # copy
+        v1 = self._path.vertices.copy()
         assert v1.shape == (2,2), 'unexpected vertices shape'
         if self.spine_type in ['left','right']:
             v1[0,1] = low