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/log.h b/lib/log.h
index ee34a4a..27f21b3 100644
--- a/lib/log.h
+++ b/lib/log.h
@@ -49,7 +49,8 @@
   ZLOG_RIP,
   ZLOG_BGP,
   ZLOG_OSPF,
-  ZLOG_RIPNG,  
+  ZLOG_RIPNG,
+  ZLOG_BABEL,
   ZLOG_OSPF6,
   ZLOG_ISIS,
   ZLOG_MASC