The API now does not follow the openflow specification quite as closely,
however I think it is much more usable. Furthermore, the Ryu plugin was
basically completely rewritten and is now more usable for general flow
manipulation.
This also adds a debug mode that just outputs the json fragments that
would be sent to ryu. At the moment, Ryu still assumes that every
request that it receives succeeds - it is not possible to get an error
message from the controller. Instead, one has to check if a flow was
added by doing a second REST request. Which seems unnecessary, and also
requires complete json parsing functionality. Hence we are not doing
that at the moment.
The alternative would be to use an external script for the actual
add-and-check-operation.
