Log Message:
Version 5.0.4 (2017-07-23)
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- This version officially supports the new Python 3.6 and PostgreSQL 9.6.
- query_formatted() can now be used without parameters.
- The automatic renaming of columns that are invalid as field names of
  named tuples now works more accurately in Python 2.6 and 3.0.
- Fixed error checks for unlink() and export() methods of large objects
  (bug report by Justin Pryzby).
- Fixed a compilation issue under OS X (bug report by Josh Johnston).