SocketManager: use a timer wheel

The maximum number of timers we need to support recently increased by an order
of magnitude, and the datastructures SocketManager was using were not efficient
at this scale. This change replaces the flat array with a timer wheel.

This increased performance in my barrier microbenchmark by 61%.
OFConnectionManager: remove unused LOCI object tracking code

This hasn't been used since barrier blockers were introduced.
Merge into master from pull request #114:
OFConnectionManager: remove unused LOCI object tracking code (https://github.com/floodlight/indigo/pull/114)
send async msgs on main cxn if selected channel is not ready
Merge into master from pull request #115:
send async msgs on main cxn if selected channel is not ready (https://github.com/floodlight/indigo/pull/115)
OFStateManager: fix warning on release builds

The variable was only used in an assertion, so the compiler warned about it on
release builds where assertions are compiled out.
Merge into master from pull request #116:
OFStateManager: fix warning on release builds (https://github.com/floodlight/indigo/pull/116)
update bigcode

* submodules/bigcode 9502bad...53b1a99 (3):
  > Merge into master from pull request #20: biglist: don't zero new elements (https://github.com/floodlight/bigcode/pull/20)
  > Merge into master from pull request #19: timer_wheel: add missing ucli handlers array (https://github.com/floodlight/bigcode/pull/19)
  > Merge into master from pull request #18: handle indianess in ip checksum calc with odd lengths (https://github.com/floodlight/bigcode/pull/18)
update infra

* submodules/infra 6898254...3ffc4c1 (7):
  > Merge into master from pull request #20: AIM: add early check for log level (https://github.com/floodlight/infra/pull/20)
  > Merge into master from pull request #19: Allow customization of the aim_main() function name. (https://github.com/floodlight/infra/pull/19)
  > Support optional AIM library constructor/destructor. - Allows module initialization in shared library builds. - Support for this feature is GCC-specific.
  > The LIBRARY_TARGETS_LAST list must be moved to the end every time a new library is added.
  > Support the LIBRARY_LAST attribute. - Libraries that indicate the LAST attribute will always be kept at the end of the global LIBRARY_TARGETS list.   The ordering between LAST libraries is arbitrary.
  > Merge into master from pull request #18: AIM: fix aim_pvs_buffer_iterate after reset (https://github.com/floodlight/infra/pull/18)
  > Merge into master from pull request #17: Support string format and duplication using AIM datatype formatting. (https://github.com/floodlight/infra/pull/17)
update loxigen-artifacts

* submodules/loxigen-artifacts 9138196...56f7807 (5):
  > Artifacts from https://github.com/floodlight/loxigen/compare/ffa04cc24b045e010c3020e2cbb8ce31cbec8895...1c5679af766cc2785f088707e83dbd5b6ac0a698
  > Artifacts from https://github.com/floodlight/loxigen/compare/27a64222e92b38e23b253657c702986c0604145a...ffa04cc24b045e010c3020e2cbb8ce31cbec8895
  > Artifacts from https://github.com/floodlight/loxigen/compare/24b6c19d413555f2aaf9129c552f5128964fefe8...27a64222e92b38e23b253657c702986c0604145a
  > Artifacts from https://github.com/floodlight/loxigen/compare/767b11df765065ac1f815ceeb27690747b67fb09...24b6c19d413555f2aaf9129c552f5128964fefe8
  > Artifacts from https://github.com/floodlight/loxigen/compare/1bc22f26bd88dae76dc749137998c16864718d5d...767b11df765065ac1f815ceeb27690747b67fb09
OFStateManager: update to new of_object_t layout
Merge into master from pull request #117:
update submodules (https://github.com/floodlight/indigo/pull/117)
add timer_wheel dependency to utests
Merge into master from pull request #113:
SocketManager: use a timer wheel (https://github.com/floodlight/indigo/pull/113)
OFConnectionManager: populate auxiliary_id field in controller connections reply
Merge into master from pull request #119:
OFConnectionManager: populate auxiliary_id field in controller connections reply (https://github.com/floodlight/indigo/pull/119)
SocketManager: restrict priority range

Previously SocketManager supported 4 billion priority levels, but we only ever
used a few of them. There are some optimizations I want to make that will be
simpler if we can restrict the number of possible priorities. This change
limits users to 5 named priorities.