CHOtest Enhancements (Emu#1)

1) Check if the ONOS-1321 could be implemented in Drake final sprint.
This depends on current ONOS metrics CLI supporting '-j' option or to print JSON output.
2) Convert the pingIPv6Hosts function in TestON mininet driver to log the output similar to mininet IPv4 pingall (i.e in a matrix fashion).
3) Add some failure cases, verify and refine SP, S2M and M2S intents types for all 3 topologies.
4) Try to see if the IPv6 pingall time could be reduced by optimizing the driver function. I have looked at the mininet even thought it does the same single packet ping to each host it takes much less time than our IPv6 ping all that we have in our driver function. Currently the IPv4 pingall across 25 hosts take an avg. of 7.05 seconds while IPv6 takes 70seconds.
5) Add checking for exceptions in all 3 ONOS nodes and adding aggregated number of exceptions to wiki report