Use txtorcon web agent

[aagbsn]

Throws out a bunch of code that is now supported by txtorcon directly.

[coveralls]

Coverage decreased (-1.9%) to 62.419% when pulling 516104b on use_txtorcon_web_agent into cd023b2 on develop.

[coveralls]

Coverage remained the same at 64.629% when pulling 8c902e6 on use_txtorcon_web_agent into 97f93b6 on develop.

[aagbsn]

This is breaking because I rebased it on top of devel; and tests using hashingReadBody fail because the expected checksum doesn't match expected from the unit tests.

[juga0]

With my changes tests are not failing (locally) because hashes don't match, but they fail sometimes because circuits fail:

    assert not failed_measurements
exceptions.AssertionError

The measurement file contains:

u'failure': u"<twisted.python.failure.Failure exceptions.Exception: Circuit failed ('CHANNEL_CLOSED')>"

[juga0]

I don't know how to reproduce it, but sometimes tests fail locally with:

Traceback (most recent call last):
  File "/home/user/bwscanner/test/test_writer.py", line 36, in <lambda>
    dl.addCallback(lambda results: walk(self.tmpdir, validate, None))
  File "/home/user/bwscanner/.tox/py27/lib/python2.7/posixpath.py", line 231, in walk
    func(arg, top, names)
  File "/home/user/bwscanner/test/test_writer.py", line 26, in validate
    assert len(fnames) == num_chunks
exceptions.AssertionError: 

test.test_writer.TestResultSink.test_send_multiple_chunk_size

[meejah]

Code changes look good to me. I don't know why some circuits are failing -- could it be a Chutney thing? In any case that seems worth investigating.

[juga0]

Meged, i'll open other issues after confirming this still happens