[Twisted-Python] twisted.trial.unittest.TestCase now now has an mktemp() method

[Pavel Pergamenshchik]

Hi.
Please don't use tempfile.mktemp() in tests -- use "self.mktemp" instead. It gives names from nice, organized directory structure under _trial_temp/, which is much better than putting stuff with cryptic names all over /tmp. I modified all tests that use mktemp. Yell at me if something suddenly breaks.

Pahan