bgpd: Add new configuration cli for eBGP and iBGP multipath.
There is support to configure this for each (AFI,SAFI), but
currently this configuration is only present for IPv4 unicast:

 maximum-paths [ibgp] <1-255>
 no maximum-paths [ibgp] [<1-255>]

* bgpd/Makefile.am
  * Add bgp_mpath.h and bgp_mpath.c to build
* bgpd/bgp_mpath.h
  * New file for bgp multipath declarations
  * define BGP_DEFAULT_MAXPATHS
* bgpd/bgp_mpath.c
  * bgp_maximum_paths_set(): Configure maximum paths for the given
    afi, safi and bgp instance
  * bgp_maximum_paths_unset(): Return maximum paths configuration to
    the default setting for the given afi, safi and bgp instance
* bgpd/bgp_vty.c
  * Define command strings for above CLI
  * bgp_config_write_maxpaths(): Outputs configuration for the given
    afi, safi and bgp instance
  * Install command elements for IPv4 unicast
* bgpd/bgp_zebra.h
  * bgp_config_write_maxpaths(): External declaration
* bgpd/bgpd.c
  * bgp_create(): Initialize bgp instance to default maximum paths setting
  * bgp_config_write_family(): Output maximum paths configuration
    for the given address family
  * bgp_config_write(): Output maximum paths configuration for
    IPv4 unicast address family
* bgpd/bgpd.h
  * struct bgp: Add storage for maximum paths configuration for
    each afi, safi
diff --git a/bgpd/bgp_mpath.h b/bgpd/bgp_mpath.h
new file mode 100644
index 0000000..f0ac836
--- /dev/null
+++ b/bgpd/bgp_mpath.h
@@ -0,0 +1,34 @@
+/* $QuaggaId: Format:%an, %ai, %h$ $
+ *
+ * BGP Multipath
+ * Copyright (C) 2010 Google Inc.
+ *
+ * This file is part of Quagga
+ *
+ * Quagga is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * Quagga is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Quagga; see the file COPYING.  If not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+
+#ifndef _QUAGGA_BGP_MPATH_H
+#define _QUAGGA_BGP_MPATH_H
+
+/* BGP default maximum-paths */
+#define BGP_DEFAULT_MAXPATHS 1
+
+/* Functions to support maximum-paths configuration */
+extern int bgp_maximum_paths_set (struct bgp *, afi_t, safi_t, int, u_int16_t);
+extern int bgp_maximum_paths_unset (struct bgp *, afi_t, safi_t, int);
+
+#endif /* _QUAGGA_BGP_MPATH_H */