babeld: Initial import, for Babel routing protocol.

* Initial import of the Babel routing protocol, ported to Quagga.
* LICENCE: Update the original LICENCE file to include all known potentially
  applicable copyright claims.  Ask that any future contributors to babeld/
  grant MIT/X11 licence to their work.
* *.{c,h}: Add GPL headers, in according with the SFLC guidance on
  dealing with potentially mixed GPL/other licensed work, at:

  https://www.softwarefreedom.org/resources/2007/gpl-non-gpl-collaboration.html
diff --git a/lib/command.c b/lib/command.c
index 4f6d184..e62a7a7 100644
--- a/lib/command.c
+++ b/lib/command.c
@@ -2400,6 +2400,7 @@
     case BGP_NODE:
     case RIP_NODE:
     case RIPNG_NODE:
+    case BABEL_NODE:
     case OSPF_NODE:
     case OSPF6_NODE:
     case ISIS_NODE:
@@ -2449,6 +2450,7 @@
     case ZEBRA_NODE:
     case RIP_NODE:
     case RIPNG_NODE:
+    case BABEL_NODE:
     case BGP_NODE:
     case BGP_VPNV4_NODE:
     case BGP_IPV4_NODE: