Log Message:
py-astor: updated to 0.6

0.6:

New features
* New astor.rtrip command-line tool to test round-tripping of Python source to \ 
AST and back to source. (Contributed by Patrick Maupin.)
* New pretty printer outputs much better looking code:
  . Remove parentheses where not necessary
  . Use triple-quoted strings where it makes sense
  . Add placeholder for function to do nice line wrapping on output
* Additional Python 3.5 support: - Additional unpacking generalizations (PEP 448)
  .  Async and await (PEP 492)
* Added Python 3.6 feature support:
  . f-strings (PEP 498)
  . async comprehensions (PEP 530)
  . variable annotations (PEP 526)
* Code cleanup, including renaming for PEP8 and deprecation of old names. See \ 
:ref:`deprecations` for more information.

Bug fixes
* Don't put trailing comma-spaces in dictionaries. astor will now create \ 
{'three': 3} instead of {'three': 3, }.
* Fixed several bugs in code generation.