Switch:

MACAddressTable:

- MACAddressTable now has removeAgedEntriesIfNeeded() for efficient MAC
  table purge.
- Added clearTable() for lifecycle.

MACRelayUnit: Added a simplified MACRelayUnit. It was necessary
because MAC address table management has been separated from
MACRelayUnitBase module.

IMACRelayUnit: This moduleinterface changed to work with MACRelayUnit.
There are no need for MAC address table configuration parameters anymore.

EtherSwitch: Added MACAddressTable.

Examples: ethernet/lans/largeNet example changed to work with the
new RelayUnit.

MACAddressTableAccess: MACAddressTable access name changed to macTable.