Comment 1 for bug 362142

As a start we are doing the following:

* For all modules that nose should skip because twisted is needed, we have defined a __test__ = {} attribute.

* For all modules that use twisted, we no longer protect the twisted import using a try/except. The assumption is that because these
tests use trial to be run, that twisted must be installed.

* We have written new trial compatible skip decorators in testing/decorators_trial.py. These have an API just like those in decorators.py