Support for BGP Large Communities

Support for BGP Large Communities

BGP Large Communities are a novel way to signal information between
networks. An example of a Large Community is: "2914:65400:38016". Large
BGP Communities are composed of three 4-byte integers, separated by a
colon. This is easy to remember and accommodates advanced routing
policies in relation to 4-Byte ASNs.

This feature was developed by:
Keyur Patel <keyur@arrcus.com> (Arrcus, Inc.),
Job Snijders <job@ntt.net> (NTT Communications),
David Lamparter <equinox@opensourcerouting.org>
and Donald Sharp <sharpd@cumulusnetworks.com>

Signed-off-by: Job Snijders <job@ntt.net>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>