of-wire json: adapt OF1.0

From: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
workaround NiciraHeader json problems
NXTSetFlowFormat json fix
of-wire json: adapt OF1.2
of-wire json: adapt OF1.3
test_parser_v12: abuse this to test to_jsondict and from_jsondict
of-wire json test: expected results
of-wire json test: a program to generate test data for unit tests
of-wire json test: change the of_protocol upstream

for now, use my fork of of_protocol, which contains necessary
fixes for our purpose.

this commit is separated from the rest of mkdata so that
it can be easily reverted when the upstream took the necessary
changes.
of-wire json test: generated data for unit test
of-wire json test: unit test
stringify: make obj_python_attrs overridable
ofproto_v1_2_parser: omit mask attribute from str() when appropriate

normalize str() outputs so that tests like str(msg1) == str(msg2)
more likely succeed..
ofproto_v1_3_parser: omit mask attribute from str() when appropriate

normalize str() outputs so that tests like str(msg1) == str(msg2)
more likely succeed..
controller: uncomment LOG.debug for testing
controller: dump json string

also, test decode/encode of json representation
controller: fix an assertion in debug code
test_parser: add debug output
test_parser: some more debug