Implementing the REST-API for debug counters

...va/net/floodlightcontroller/core/web/CoreWebRoutable.java

...a/net/floodlightcontroller/debugcounter/DebugCounter.java

...lightcontroller/debugcounter/DebugCounterGetResource.java

...ghtcontroller/debugcounter/DebugCounterResetResource.java

...ightcontroller/debugcounter/DebugCounterResourceBase.java

...ghtcontroller/debugcounter/DebugCounterStateResource.java

...oodlightcontroller/debugcounter/IDebugCounterService.java

...t/floodlightcontroller/debugcounter/NullDebugCounter.java

...tcontroller/devicemanager/internal/DeviceManagerImpl.java

...va/net/floodlightcontroller/topology/TopologyManager.java