Remove references to testrecorder

zope.testrecorder comes with a whole swath of dependencies, in particular the extensive pinning in http://good-py.appspot.com/release/zope/2.13.10.
This commit removes it entirely, since it can be installed and run just as well from outside the repository.

Is anyone actively using testrecorder?
If yes, is there a way to install it without the extensive pinning?