Added a function to receive status from the switch through the
openflow controller. (not yet implemented anywhere)
The flow_mod and flow_stats function now have default values which
report that the function is not implemented when they're called but
no plugin has registered its functions for them.
the openflow framework does now use events to signal
the success or failure of openflow commands, further
the reporter framework is used to log errors.
added bro unique cookie, so the framework can recognize
which flows it installed and which not.
documented all of the code.
the code style should now me more like the rest of the
bro code.
