Add MAC mapping feature.

MAC mapping is virtual network mapping based on MAC address and VLAN ID.
It can associate one or more MAC addresses with a vBridge.

Note that VTN Coordinator does not support MAC mapping yet.

Other changes:

  * API version of VTN Manager is changed to 2.

Change-Id: I98d1522753897595dc15ae494852d5ed3e5399f8
Signed-off-by: Shigeru Yasuda <s-yasuda@da.jp.nec.com>
Merge "Add MAC mapping feature."