Update to link discovery manager.  LLDPs are sent every one second; with a three second timeout on ports where links were already found.  On ports where links are not present, LLDPs are sent once in every 15 seconds.

Bug fix: handleLLDP() method uses incorrect port variable when getting the state of the packet-in port.

Bug fix: prevCluster assignment is changed to reflect the L2 domain ID of the prev entity.  It was possible for cur and prev to be swapped when duplicate attachment points were detected, where the prevCluster could have the wrong assignment.

Correct the set/get of TOS bits in OFMatch. The 6-bits of DSCP need to be top 6-bits of the network ToS byte.

Add a unit test that makes sure an exception is thrown when someone tries to remove a switch from the active switch map.

BSC-2116

BSC-2116

Change OFPacketIn.MINIMUM_LENGTH from an int to a short. OFPacketIn.setTotalLength() expects a short.

During flow reconciliation, device manager should not call learnDeviceByEntity, which would incorrectly update timestamps of entities existing in flow cache. It should call findDeviceByEntity instead.

If we cannot find an entity in the primary index we need to
classify it into an IEntityClass and the search in the class index.

* Fixed couple of bugs in Device.getIPv4Addresses().
* Add more debugging output to DeviceManagerImpl

* implement findDestDeviveByEntity()
* findDevice() and findDestDevice() will now throw an exception of the
  supplied fields are not sufficient for the lookup
* test and comment polishing
* reorganizing testing code

[BSC-1838]

(These icons were designed from scratch by me with ASL 2.0 license.)
Nodes are now labeled with their name (DPID or IP+MAC).
Added a hack to ignore multiple attachment points for hosts, since
Floodlight's concept of attachment points doesn't correspond to the
physical topology.