Make the hearbeat test a bit faster
The changes to WSGIProxy had been merged upstream.
Improve coverage of output.py
Some doc for those  who don't know what 'hush' means
Return total_seconds() rather than sec, ms.

The seconds and microseconds properties are not returning to total number of
seconds or miliseconds, like we would expect it to do.

Imagine you have a delta of 1minute and 30s, .seconds would return 30 and not
90 like expected.
Fix the APIs fo the NullOutput.
Add tests for the NullOutput.
Add a test for the custom JSONEncoder we have.
Use total_seconds() for the elapsed time.
Broken merge.