Merge into master from pull request #206:
update submodules (https://github.com/floodlight/ivs/pull/206)
ivs: increase SocketManager socket limit

We use a few sockets per port (though not all are registered with
SocketManager), so the limit of 1024 was a scalability problem.
ivs: increase RLIMIT_NOFILE to match SOCKETMANAGER_CONFIG_MAX_SOCKETS
Merge into master from pull request #207:
increase maximum number of file descriptors to 4096 (https://github.com/floodlight/ivs/pull/207)
update indigo

* submodules/indigo 21e81db...ad17298 (1):
  > Merge into master from pull request #156: OFStateManager: remove support for expiring flows in Forwarding (https://github.com/floodlight/indigo/pull/156)
update loxigen-artifacts

* submodules/loxigen-artifacts d54f9d3...71688a9 (2):
  > Artifacts from https://github.com/floodlight/loxigen/compare/7c85d69af77c5b3f18ea33b7e54f97e0537bf340...f2cc055aa7e8e8f946dc1216318c0c9d8b8f4f39
  > Artifacts from https://github.com/floodlight/loxigen/compare/e8bc0f2022ad98d99f282b0c6d864f387198b8f4...7c85d69af77c5b3f18ea33b7e54f97e0537bf340