Adding new files: interface.go and interface_test.go
Adding InterfaceDefineXMLFromFile,InterfaceDefineXML and tests
Adding Create,Destroy interface and tests
Adding  LookupInterfaceByName, LookupInterfaceByMACString and tests
Adding GetConnect, IsActive, GetMACString and tests
Adding GetName,GetXMLDesc,Undefine and tests
Remove virInterface.GetConnect
Add VirInterface.Free as per #14