an obscure, undocumentated feature so no test was added. Closes
issue #1101399.

There should be no other effect than a small decrease in memory use.
Patch by Christopher Tur Lesniewski-Laas.

code, adds checks for stdin/out/err, cwd, and sys.path, and adds a new
section in the summary for tests that modify the environment (thanks to
Ezio Melotti for that suggestion).

makeunicodedata now generates double literals

thread, and mutating it from another one.  Patch by Scott Dial.

Fix broken links found by "make linkcheck".  scipy.org seems to be done right now, so I could not verify links going there.

Add the Python FAQ lists to the documentation.  Copied from sandbox/faq.  Many thanks to AMK for the preparation work.