NetworkLayer: Removed getInterfaceModule from InterfaceEntry.

This function returned the module that created the interface which is not the interface module.
NetworkLayer: Renamed getNetworkInterfaceModule to getInterfaceModule.
NetworkLayer: Fixed interfaceModule member to really hold the interface module.
Common: Removed obsolete and unpredictable ModuleAccess class.
Common: Removed obsolete and unpredictable findModuleWherever*.
diffserv: CID 77588, 77637, 77652, 77676, 77878, 77898: uninitialized member variables
diffserv: CID 77725 Structurally dead code