python - fe: Refactor tracenull Fitting.

Log Message:
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Refactor tracenull Fitting.

The benefits of the "protection" that creating hard bound classes and functions
costs more than it is worth. The benefits are actually few and questionable at
best.

Refactor things so everything relative to the connection is not built in
__new__, rather, likely, give it a connection as an argument.
[Bugs are likely to be about, but tests pass.]

Modified Files:
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    fe/src:
        tracenull.py (r1.12 -> r1.13)
        (http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/fe/src/tracenull.py.diff?r1=1.12&r2=1.13)