update bigcode

* submodules/bigcode a0fd12e...2c751ca (1):
  > Merge into master from pull request #25: iof_init() enhancement (https://github.com/floodlight/bigcode/pull/25)
update loxigen-artifacts

* submodules/loxigen-artifacts 316a4c3...4787033 (2):
  > Artifacts from https://github.com/floodlight/loxigen/compare/f8bbbe2cfa971fc38dbbd49ec09bbf149bed4685...1d8819a23e3decd195baa2d0306e9d887b17a50f
  > Artifacts from https://github.com/floodlight/loxigen/compare/a5f488a034bcf3815716be675e071c87f3e7973b...f8bbbe2cfa971fc38dbbd49ec09bbf149bed4685
update switchlight-common

* submodules/switchlight-common 9b94b93...75e734c (1):
  > Merge into master from pull request #53: fix traceroute (https://github.com/floodlight/switchlight-common/pull/53)
update bigcode

* submodules/bigcode 2c751ca...bfe3620 (1):
  > Merge into master from pull request #26: Allow NULL to specify no formatting for pop-scope. (https://github.com/floodlight/bigcode/pull/26)
update loxigen-artifacts

* submodules/loxigen-artifacts 4787033...94f034f (1):
  > Artifacts from https://github.com/floodlight/loxigen/compare/1d8819a23e3decd195baa2d0306e9d887b17a50f...8dcf8a2618adfd827a20169c34401ed04a25d383
Merge into master from pull request #159:
Update submodules (https://github.com/floodlight/ivs/pull/159)