Life is beatiful once again.

by signals on platforms using pthreads.  Patch by Reid Kleckner.

Issue 10534, difflib: tweak doc; test new SequenceMatcher instance attributes; avoid unneeded lists of SM.b2j keys and items in .__chain_b. Do not backport.

or `python -m test` should be used instead.

socket timeout of 30 when it checks for resource.  Explicit overrding (like
setting the 10) wont exhibit consistent behavior when tests are outside context
manager. So, settting it 30.

Patch by Simon Cross, crasher test code by Martin von Löwis.