values for socket.getaddrinfo().
commiting and pushing it at my discretion.

Conflicts:
	src/bin/xfrout/tests/xfrout_test.py.in

quickly discussed on jabber.

suggested in review.

LIBRARY_PATH_PLACEHOLDER

which is not (at least yet) applicable.  also added a note about the
difference between the C++ doc and the python version derived from it.

This is not directly related to the subject of this ticket, but
would be necessary to complete the TSIG + TC bit support.

- explicitly imports the json module in __init__.py (this should actually be
  done at the isc package level, but we now don't rely on the implicit
  side effect).
- get the reference to the dumps() callable at the RequestLoader initialization
  time and keep it thereafter.  This would also slightly improve runtime
  performance.

... and use it in the Python unit tests that generate logging output.

Shortened the name to resetUnitTestRootLogger() to make it a bit less
of a mouthful.

Add a reset logging function to specific tests to ensure that the
logging is routed to the stream selected by the B10 environment
variables prior to each test that generates messages.

Removes (by default) one of the remaining logging messages identified
in the review.