Log Message:
py-netaddr: update to 0.7.19

Release: 0.7.19:

* added a new SubnetSplitter class for those looking to divide up subnets.
  Thanks alanwill and RyPeck and those on (Stack Overflow discussion).

* removed bundled pytest dependency code for "python setup.py test".

* setup.py now uses setuptools only (no more distutils) and setup_egg.py removed.

* cleaned up INSTALL docs so they accurately reflect current Python packaging.

* fixed broken parsing, generating and reading of IEEE index files when switching
  between Python 2.x and 3.x.