- Remove configuration settings from removed _sha3.vcxproj
- Don't try to build configurations of _testembed that don't exist
  (namely, PGInstrument and PGUpdate)

base32, ascii85 and base85 codecs in the base64 module, and delay the
initialization of the unquote_to_bytes() table of the urllib.parse module, to
not waste memory if these modules are not used.

correct the fix for #20637; allow slot descriptor inheritance to take place before creating cached keys

Patch by Ryan Kelly, karl, and Nikolaus Rath.

self parameter is implicit. Mention also that communicate() and wait() are
coroutines.

Patch by Andreas Schwab.

We changed a few details of the pip integration over the course
of the Python 3.4 beta and release candidate cycle, but I hadn't
updated the What's New entry appropriately.

The Py2/Py3 split on POSIX and the generally challenges of
dealing with parallel installs means we haven't attained
complete consistency across all environments, but hopefully
this updated text is clearer about the end result.

Relevant to issue #20909.

closes #20931