OpenFlow 1.3 role request tests

See OpenFlow spec 1.3.3, sections 6.3.4 and 7.3.9.

The RoleSwitch test is disabled because it requires special switch
configuration (the switch must attempt to connect to two controllers).
Merge into master from pull request #92:
update pyloxi to 026ff024585f1588a7f11fa4c1a9a48d44dc098d (https://github.com/floodlight/oftest/pull/92)
Merge into master from pull request #83:
OpenFlow 1.3 role request tests (https://github.com/floodlight/oftest/pull/83)
update pyloxi to floodlight/loxigen-artifacts@5c5ec9b3142bf91524c29a00a26d464dab1f21d9