minor toString fix in Device

2 - Move the learning switch table outside of the IOFSwitch and into the LearningSwitch module.
3 - Create a REST API for the LearningSwitch module to get the learned table. Available at "/wm/learningswitch/switch/{DPID or 'all'}/json".

Correct race condition in device learning and topology, remove deviceManager from listening linkEvent

This reverts commit 0ae432f4.

Conflicts:

	src/main/java/net/floodlightcontroller/devicemanager/internal/DeviceManagerImpl.java

2 - Update module HA role change actions
3 - Add unit tests for HA role changes

module provides no services.

2 - Log PacketIns with no payload and stop processing
3 - Remove unused IOFController interface

This reverts commit 51ca40a3.

Conflicts:

	src/main/java/net/floodlightcontroller/devicemanager/internal/DeviceManagerImpl.java