and test_support.run_classtests() into run_unittest()
and use it wherever possible.

Also don't use "from test.test_support import ...", but
"from test import test_support" in a few spots.

From SF patch #662807.

Right now the test cases create a files and a directory in the temp.
directory.  Raymond suggested checking files in to the test/ directory,
simplifying the setup/teardown methods; is that worth doing?