add switchlight-common submodule
update bigcode

* submodules/bigcode 3edb087...a7e27ae (10):
  > Remove trailing whitespace.
  > Update name.
  > Merge into master from pull request #5: vpitool and VPI TAP interface. (https://github.com/floodlight/bigcode/pull/5)
  > Merge into master from pull request #2: Support for LACP and LLDP Parsing (https://github.com/floodlight/bigcode/pull/2)
  > Set ROOT.
  > Merge into master from pull request #1: Update module autogeneration scripts. (https://github.com/floodlight/bigcode/pull/1)
  > Latest.
  > Publishing updates.
  > Initial.
  > Documentation updates.
ivs: link in LLDP/LACP agents

Not integrated into packet processing or OpenFlow message handling yet.
Merge into master from pull request #75:
link in LLDP/LACP agents from switchlight-common (https://github.com/floodlight/ivs/pull/75)