Check for more rcodes and various properties needed in the wildcard
test. Add a `name` module for various dns.name.Name operations (with
`prepend_label` function only now).
Expose `timeout` as a parameter of `query.tcp`/`query.udp`.
Remove conf.sh.in and move the environment variables into isctest/vars
python package. This enabled the removal of an ugly pytest hack which
loaded and parsed these variables from the environment.
Create a utility package for code shared by the python tests. The
utility functions should use reasonable defaults and be split up into
modules according to their functionality.
Ensure assert rewriting is enabled for the modules to get the most
useful output from pytest.
