OFConnectionManager: reject OF_BSN_SET_SWITCH_PIPELINE_REQUEST from a slave
Merge into master from pull request #129:
OFConnectionManager: reject OF_BSN_SET_SWITCH_PIPELINE_REQUEST from a slave (https://github.com/floodlight/indigo/pull/129)
SocketManager: fix unregistering next timer in the ready list

If a timer unregistered the timer after it in the ready list, we'd crash
because LIST_FOREACH_SAFE saved a pointer to the next entry. The underlying
problem is that we're iterating over a list where any element can be removed by
the timer callback.

The fix is to treat the ready list as a queue. The slight difficulty is that
timers with a different priority level need to remain on the ready list. Doing
this while treating the ready list as a queue requires a temporary list.

Now a ready timer can be either on the real ready list or a temporary list.
This has gotten complicated enough that I added an explicit state to the timer
entry so the rest of the code knows whether ready_links or timer_wheel_entry
is valid.
SocketManager: add some comments to process_timers
Merge into master from pull request #130:
SocketManager: fix unregistering next timer in the ready list (https://github.com/floodlight/indigo/pull/130)
OFConnectionManager: send async controller connections message to slaves

The slaves need this to decide whether to become master.
Merge into master from pull request #131:
OFConnectionManager: send async controller connections message to slaves (https://github.com/floodlight/indigo/pull/131)
OFConnectionManager: remove dead code

Clang 3.4 complains about this.
OFStateManager: fix tautological comparison

Found by Clang 3.4.
Add more port counters.
Merge into master from pull request #133:
fix warnings from Clang 3.4 (https://github.com/floodlight/indigo/pull/133)
Merge into master from pull request #132:
Add more port counters. (https://github.com/floodlight/indigo/pull/132)
OFConnectionManager: fix clang-analyzer warning

The analyzer wasn't convinced that cur_node would be non-NULL (and that the iov
would be initialized) if left > 0. I don't think there's an actual bug here,
but better to be safe.
OFStateManager: fix clang-analyzer warning

The analyzer assumed that the return value from ft_entry_set_effects could be
greater than zero. If this happened the entry would not be returned by
ft_entry_create, but ft_add would think it was returned.
OFStateManager: populate table_id in bsn_table_checksum_stats_entry
Merge into master from pull request #134:
OFStateManager: populate table_id in bsn_table_checksum_stats_entry (https://github.com/floodlight/indigo/pull/134)
Merge into master from pull request #135:
fix clang-analyzer warnings (https://github.com/floodlight/indigo/pull/135)
OFStateManager: fix undeclared variable in assertion

Now that asserts reference the expression even when the assert is disabled,
this hack is no longer needed.
Merge into master from pull request #136:
OFStateManager: fix undeclared variable in assertion (https://github.com/floodlight/indigo/pull/136)
OFConnectionManager: drop more types of messages when the write buffer partially fills

Refactored to classify certain message types as "noncritical" and drop them
when reaching a high water mark.

Previously only OF_FLOW_REMOVED and OF_PACKET_IN would be dropped. This adds
OF_BSN_FLOW_IDLE, OF_BSN_ARP_IDLE, and OF_BSN_PDU_RX_TIMEOUT.