Replace txagentwithsocks in httpt template
Finish adding support for using txsocksx in HTTP templat in HTTP templat in HTTP templat in HTTP template

* Make sure we are using the TrueHeaders and in SOCKSAgent and Agent
Fix unittest for true headers..
Add support for using txsocksx inside of oonibclient.
Start adding support for using txsocksx inside of oonibclient.

There is some badness happening because we use the httpo (HTTP over Tor Hidden
Service) as the scheme name.
Take an instance rather than class

Measurements should be able to take an instanced class so that the
resulting report can be shared between several Measurements.
Add postProcessor support to NetTest

If a NetTestCase has multiple test_ methods, then the report write shall
not occur until all of the individual Measurements have completed.

This also changes the postProcessor API slightly; postProcessors are now
expected to return a report instance. If a postProcessor is not
supplied, then the report object from the instanced NetTestCase class is
passed to Report.write()
Check to see if setUp was already called correctly

The report dict is already created in the constructor, so we look to see
if instead the input argument was already set.
Use our TrueHeaders version of the SOCKS5Agent in oonibclient
str().replace() returns a copy and does not modify in place.
Don't look up helpers if we have already specified a helper.

Note: we will need to remove the default helpers in ooni's NetTests.
Do not set default backends

If a valid default backend is specified, the bouncer will not look up test helpers
Use a string for the control_resolver key

If a tuple is used as the report key, it will break the yaml parser.
Add GeoIP city data to report
Decode correct protocol

No wonder it didn't work.
Add keys for each traceroute type to report
Update README.md
Merge pull request #211 from TheTorProject/feature/support_postprocessor_api

Feature/support postprocessor api
Refactor the code of the post processor to work properly.
Merge pull request #219 from TheTorProject/fix/default_backends_break_helper_lookup

Fix/default backends break helper lookup