add bsn_time extension

This extension allows the controller to get a timestamp from the switch. This
will differ from the controller's time due to network latency, TCP queueing,
and queuing in the switch software.
wireshark: write output file to correct directory
Merge into master from pull request #129:
wireshark: write output file to correct directory (https://github.com/floodlight/loxigen/pull/129)
Merge branch 'master' of github.com:floodlight/loxigen
Fix name mismatch
Merge branch 'master' of github.com:ronaldchl/loxigen
Merge into master from pull request #130:
Fix name mismatch for BSN_IN_PORTS_128 (https://github.com/floodlight/loxigen/pull/130)
loci: add time_ms show macro
Merge into master from pull request #124:
add bsn_time extension (https://github.com/floodlight/loxigen/pull/124)
openflow_input: fix of_group_desc_stats_entry.group_type

use enum ofp_group_type for consistency with the group_mod messages
Merge branch 'master' of github.com:floodlight/loxigen