py-pygraphviz: add suports for python 3

[mojca (Mojca Miklavec)]

Not sure what type of ticket this is, but following ​PR #76 I tried to add subports for python 3.4 and 3.5 to py-pygraphviz and failed.

I tested versions 1.1, 1.3, 1.4rc1. I suspect that 1.1 is not compatible, 1.3 is most likely missing a file:

DEBUG: system:  cd "/path/to/py35-pygraphviz/work/pygraphviz-1.3" && /opt/local/Library/Frameworks/Python.framework/Versions/3.5/bin/python3.5 setup.py --no-user-cfg build 
Traceback (most recent call last):
  File "setup.py", line 16, in <module>
    from setup_commands import AddExtensionDevelopCommand, AddExtensionInstallCommand
ImportError: No module named 'setup_commands'

1.4rc1 fails with

running install
dpkg-query: no path found matching pattern *graphviz*
Trying dpkg
Traceback (most recent call last):
  File "setup.py", line 93, in <module>
    tests_require=['nose>=0.10.1', 'doctest-ignore-unicode>=0.1.0', 'mock>=1.3'],
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/distutils/core.py", line 148, in setup
    dist.run_commands()
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/distutils/dist.py", line 955, in run_commands
    self.run_command(cmd)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/distutils/dist.py", line 974, in run_command
    cmd_obj.run()
  File "/path/to/py35-pygraphviz/work/pygraphviz-1.4rc1/setup_commands.py", line 44, in modified_run
    self.include_path, self.library_path = get_graphviz_dirs()
  File "/path/to/py35-pygraphviz/work/pygraphviz-1.4rc1/setup_extra.py", line 156, in get_graphviz_dirs
    include_dirs, library_dirs = _try_configure(include_dirs, library_dirs, _dpkg_config)
  File "/path/to/py35-pygraphviz/work/pygraphviz-1.4rc1/setup_extra.py", line 115, in _try_configure
    i, l = try_function()
  File "/path/to/py35-pygraphviz/work/pygraphviz-1.4rc1/setup_extra.py", line 47, in _dpkg_config
    output = S.check_output(['dpkg', '-S', 'graphviz'])
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/subprocess.py", line 626, in check_output
    **kwargs).stdout
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/subprocess.py", line 708, in run
    output=stdout, stderr=stderr)
subprocess.CalledProcessError: Command '['dpkg', '-S', 'graphviz']' returned non-zero exit status 1
Command failed:  cd "/path/to/py35-pygraphviz/work/pygraphviz-1.4rc1" && /opt/local/Library/Frameworks/Python.framework/Versions/3.5/bin/python3.5 setup.py --no-user-cfg install --prefix=/opt/local/Library/Frameworks/Python.framework/Versions/3.5 --root=/path/to/py35-pygraphviz/work/destroot 
Exit code: 1

[kurthindenburg (Kurt Hindenburg)]

In 37a845c1654264b291e4a4b025b9cb52741ed6cd/macports-ports:

py-pygraphviz: move to github; update to 1.4rc1

Add python 34, 35, 36 - enable tests (lot of failures)

closes #52995