Make BasicFactory a singleton

...va/net/floodlightcontroller/core/internal/Controller.java

.../floodlightcontroller/core/internal/OFMessageDecoder.java

...main/java/org/openflow/protocol/factory/BasicFactory.java

...et/floodlightcontroller/core/internal/ControllerTest.java

...t/floodlightcontroller/core/internal/RoleChangerTest.java

...loodlightcontroller/core/test/MockFloodlightProvider.java

...ava/net/floodlightcontroller/core/test/PacketFactory.java

...ller/linkdiscovery/internal/LinkDiscoveryManagerTest.java

...va/net/floodlightcontroller/util/OFMessageDamperTest.java

src/test/java/org/openflow/protocol/BasicFactoryTest.java

src/test/java/org/openflow/protocol/OFErrorTest.java

...est/java/org/openflow/protocol/OFStatisticsReplyTest.java

...t/java/org/openflow/protocol/OFStatisticsRequestTest.java

src/test/java/org/openflow/protocol/OFVendorTest.java

src/test/java/org/openflow/util/OFTestCase.java