Mac/FreeBSD Network Facts implementation

Uses a generic BSD Network class, which uses ifconfig and
parses crap out of it.  Modifies the Network __new__
implementation to search further down the subclass
tree
Restructured inheritance of BSD network classes

Now all BSD network classes directly inherit from Network as well as from the generic BSD network class.  This removes the need for itersubclasses().
Broke BSD ifconfig parser into chunks for subclassing

This allows minor changes to be handled by adding a new
parse line function to the subclass
Merge branch 'setup_network2' of git://github.com/nigelm/ansible into devel