py-modulegraph: updated to 0.16

0.16:
* Add LICENSE file to distribution
* Don't rely on pkg_resources to calculate package version
* Replace use of ``optparse`` by ``argparse`` as the former is deprecated
* Attempt to reduce the maximum recursion needed to create the ModuleGraph
* Don't include the file type in the result from ``zipio.getmode``
* Fix mismatched indents/dedents in ModuleGraph debug output

(adam)