Monitoring: initial version
Merge branch 'issue261' of https://github.com/akorosmezey/of_protocol into akorosmezey-issue261
Reinstate encoding of ofp_experimenter_request
Remove length field from flow update records

The length can be calculated from the contents; no need to keep a
separate count.
Don't treat flow update pause/resume specially

The updates field always contains a list of records for consistency.
Update type for ofp_flow_monitor_reply