OpenBSD older than 5.5

Vajrasky Kok.

Replace it with correct logic that raises ValueError for bad input.
Issues #8478 and #12691 reported the incorrect logic.
Add an Untokenize test case and an initial test method.

also typo. Patch written by Vajrasky Kok.

aways from zero, instead of rounding towards zero.

It should make test_asyncio more reliable, especially test_timeout_rounding() test.

Nowadays it is likely that people will have Sphinx installed,
and if not, they will know how to install it.

This also simplifies life a lot for distribution packagers,
who typically do not want the doc build process to connect
to external web resources.

Patch by Vajrasky Kok.

- now also allows POSIX installation with SSL/TLS missing
- a goal for pip 1.6 is to allow local use without SSL/TLS