'level' is specified but no __package__.

This brings the function inline with builtins.__import__(). Thanks to
Manuel Jacob for the patch.

* The Windows-specific binary notice was probably a Python 2 thing
* Make it more obvious gettarinfo() is based on stat(), and that non-ordinary
  files may need special care
* The file name must be text; suggest dummy arcname as a workaround
* Indicate TarInfo may be used directly, not just via gettarinfo()

* Add headings for each concrete and mix-in class and list methods and
  attributes under them
* Fix class and method cross references
* Changed RequestHandler to BaseRequestHandler and added class heading
* Pull out Stream/DatagramRequestHandler definitions
* Reordered the request handler setup(), handle(), finish() methods
* Document constructor parameters for the server classes
* Remove version 2.6 not relevant for Python 3 documentation

the same values as open().

the same values as open().

Patch by Aviv Palivoda.

Patch from Chi Hsuan Yen.

versions 10.5 or higher.  Original patch by A. Jesse Jiryu Davis.

Some of the inspiration and wording is taken from the text of PEP 498 by Eric
V. Smith, and the existing str.format() documentation.

Microbenchmarks show 2-2.5x improvement.  Built-in 'divmod' function
is now also ~10% faster.

-m timeit -s "x=22331" "x//2;x//-3;x//4;x//5;x//-6;x//7;x//8;x//-99;x//100;"
with patch: 0.321          without patch: 0.633

-m timeit -s "x=22331" "x%2;x%3;x%-4;x%5;x%6;x%-7;x%8;x%99;x%-100;"
with patch: 0.224          without patch: 0.66

Big thanks to Serhiy Storchaka, Mark Dickinson and Victor Stinner for
thorow code reviews and algorithms improvements.

Different solution from 3.5.