http.server, imghdr, mailcap, mimetypes, xml.etree.

http.server, imghdr, mailcap, mimetypes, xml.etree.

Major changes:

- StreamReader.readexactly() now raises an IncompleteReadError if the
  end of stream is reached before we received enough bytes, instead of
  returning less bytes than requested.

- Unit tests use the main asyncio module instead of submodules like events

- _UnixWritePipeTransport now also supports character devices, as
  _UnixReadPipeTransport. Patch written by Jonathan Slenders.

- Export more symbols: BaseEventLoop, BaseProactorEventLoop,
  BaseSelectorEventLoop, Queue and Queue sublasses, Empty, Full

between the resolution of the BaseEventLoop.time() method and the resolution of
the selector. The granuarility is used in the scheduler to round time and
deadline.

EpollSelector.select() round again the timeout towards zero

select.epoll.poll() rounds again the timeout towards zero

towards zero

LZMACompressor.__init__ is left not converted.

a2b_qp() now accepts keyword arguments.
All "ascii" parameters is renamed to "data" for consistancy with a2b_qp().

also specified.

On Windows os.open() error message doesn't contain file name.

Add also entries in the table of content for each synchronization primitive
class.

PyMethodDescr_Type, _PyMethodWrapper_Type, and PyWrapperDescr_Type)
have been modified to provide introspection information for builtins.
Also: many additional Lib, test suite, and Argument Clinic fixes.

- Alex J Burke noticed a debugging raise in the commit that
  fixed the original bug reported in issue 20317
- this showed that multiple iterations through the affected
  loop wasn't actually being tested