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 #83:
OpenFlow 1.3 role request tests (https://github.com/floodlight/oftest/pull/83)