Adding a simple broadcast handler

Adding a simple broadcast handler

1.) An interface IBroadcastHandler for enabling/disabling and controlling
    the mode of operation for a module that provides broadcast handling and
    a function to broadcast a packet.
2.) An implementation of that interface, SimpleBroadcastHandler, that both
    handles broadcast traffic received from the DataPacketService and
    provides a way to braodcast a synthetically-generated packet.

There are four modes only two of which have currently been extensively
tested: DISABLED and BROADCAST_TO_HOSTS.

Change-Id: I6ab6042ad7ec08b819a8840e8518022c7805f4e2
Signed-off-by: Colin Dixon <ckd@us.ibm.com>