Version 1.3.3

Features

Introduce handlers and setters to neighbor_table.h. Users can now
fully interact with the ARP and IPv6 Neighbor tables, and receive
notifications when neighbors are learned or expire.
Expose a lock in sdk.h so users can safely use the SDK across
multiple threads.

Breaking change: the metric is no longer exposed on ip_route
objects. This value was never configurable, and made ip_route_t's
more confusing.
Breaking change: fib.h's APIs have been updated to use key
types instead of an ip_prefix_t and uint64_t directly. This
will let us future-proof this API as we add support for VRFs and
other features.
Bug fix: previously, adding a nexthopgroup via while in resync
mode would cause an error if the via already existed before resync
started. This behavior is now fixed.
Bug fix: Use an initializer list in eth.h for setting an array
ofbytes. This was causing issues on newer versions of GCC.
policy_map.h now #include <functional>, which was causing build
issues on certain platforms.
Print clear error messages during configure (instead of the usual
gcc giberish) when the user's compiler has incomplete C++11
support.
Clean up the DirectFlowProgrammer.py example
Add a new PolicyRouter example, a python agent which monitors a
file and turns its contents into PBR configuration.
A new simple example called InterfaceMonitor.py to demonstrate
reactions to interfaces going down.