Fix unittests for nettest
Refactoring of NetTestLoader

* Make it clear that calling one of those methods can be extremely dangerous
* Kill a bug spotted thanks to unittesting
Rename private option to test_file to separate it from test string.
Fix director unittest
Remove now superfluos runner unittest
Change how we pass arguments to the nettest loader

* Explicit the passing of the nettest file argument
Make the starting of tests more robust.
Add more debugging to managers
Set the default collector via the command line option
Update test decks with the proper key
Fix so that parsing of test decks works properly
Fix typo in test deck before_i_commit
Raise NoMoreReporters exception on failure
Add option to disable the default collector

* More robust startup process
Parametrize task timeout and retry count
Make the starting of ooniprobe via cmd line more robust
Make reporting more robust

Get rid of ridiculous logic that uses a deferred list, instead keep track of
the report task via a single deferred.
Pass the IP address of the probe instead of an object
Final cleanup and bugfixing for task_manager
Clean up tests for updated ooni codebase