first cut at supporting nwaddr w mask
whoops, should use mask instead of value here
more comments
clarify comments
quicktest support for masked IP addrs

one subtlety is that m_mask = None is equivalent to m_mask = Some 0
so change how Match.marshal works to make quicktest happy about this
Merge pull request #50 from adferguson/of10_wildcards

OpenFlow 1.0 IP addr wildcards