Added management interface to each daemon

This includes vxsnd-ctl and vxrd-ctl user utilities to query the
respective daemons for state.  Communication is via a unix-domain
socket.  The '-h' option to each utility gives usage information.

These utilities use python-docopt module which must be installed
Reflect peer list back to vxrd and add selfrep capability

On receiving a refresh message from vxrd, the vxsnd reflects back to
the vxrd the peer vteps for each of the vxrd's VNIs.  The vxrd can
then use this list for self replication.  If enabled, vxrd will
configure the vxlan interfaces with the peernodes, reconfiguring when
the list changes.