matplotlib/matplotlib — pull request #2385 by davidovitch (2013-09-05 15:41:59+00:00)
Title: fix forgotten cStringIO replacement when replacing 2to3 with six

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Error introduced with commit f4adec7b56 (Use six instead of 2to3). For Python2 cStringIO was still being used, but the import statement was removed. Both Python2 and 3 should use io.StringIO, which is the same as elsewhere in the code.