Create mockup package for FloodlightMockClient.
Change switchId to be a String in IFloodlightStaticFlowPusherClient.
Remove dependency from floodlight.

Our code no longer imports floodlight classes. Hence, there is no longer need for floodlight dependency in platform.
org.opennaas.extensions.openflowswitch.driver.floodlight communicates with floodlight, but does not use floodlight defined classes.
Merge pull request #666 from isartcanyameres/fix/of-switch-floodlight-client

Fix/of switch floodlight client cleanup