Use @implementer instead of implements in TTwisted.py

As per zope.interface 4.0.0 changelog

• Deprecate the “class advice” APIs from zope.interface.declarations: implements, implementsOnly, and classProvides. In their place, prefer the equivalent class decorators: @implementer, @implementer_only, and @provider. Code which uses the deprecated APIs will not work as expected under Py3k.

https://pypi.python.org/pypi/zope.interface

PR incoming, patch is simply output of zope-2to3 -wn lib/py/src/transport/TTwisted.py