* Close explicitly queues to make sure that we don't leave dangling
  threads
* test_queue_in_process(): remove unused queue
* test_access() joins also the process to fix a random warning

bpo-26762: test_multiprocessing now detects dangling processes and
threads per test case classes:

* setUpClass()/tearDownClass() of mixin classes now check if
  multiprocessing.process._dangling or threading._dangling was
  modified to detect "dangling" processses and threads.
* ManagerMixin.tearDownClass() now also emits a warning if it still
  has more than one active child process after 5 seconds.
* tearDownModule() now checks for dangling processes and threads
  before sleep 500 ms. And it now only sleeps if there is a least one
  dangling process or thread.

bpo-26762: Fix more dangling processes and threads in
test_multiprocessing:

* Queue: call close() followed by join_thread()
* Process: call join() or self.addCleanup(p.join)

I found a tiny typo in the curses how-to: changed 'Thy' to 'The' on line 68.

* bpo-30980: Fix close test to fail

test_close_twice was not considering the fact that file_wrapper is
duping the file descriptor. Closing the original descriptor left the
duped one open, hiding the fact that close protection is not effective.

* bpo-30980: Fix double close protection

Invalidated self.fd before closing, handling correctly the case when
os.close raises.

* bpo-30980: Fix fd leak introduced in the fixed test

Catch also ssl.SSLEOFError in NetworkedNNTPTests setUpClass().
EOFError was already catched.

test_level() of _test_multiprocessing._TestLogging now uses regular
processes rather than daemon processes to prevent zombi processes
(to not "leak" processes).

In configdialog: Document causal pathways in create_font_tab docstring.  Simplify some attribute names. Move set_samples calls to var_changed_font (idea from Cheryl Sabella).  Move related functions to positions after the create widgets function.

In test_configdialog: Fix test_font_set so not order dependent.  Fix renamed test_indent_scale so it tests the widget.  Adjust tests for movement of set_samples call.  Add tests for load functions.  Put all font tests in one class and tab indent tests in another.  Except for two lines, these tests completely cover the related functions.

* Document causal event pathways in docstring.
* Simplify some attribute names.
* Rename test_bold_toggle_set_samples to make test_font_set fail.
* Fix test_font_set so not order dependent.
* Fix renamed test_indent_scale so it tests the widget.

* Fix #30919: shared memory allocation performance regression in multiprocessing

* Change strategy for Arena directory choice

* Add blurb

* bpo-26732: fix too many fds in processes started with the "forkserver" method

A child process would inherit as many fds as the number of still-running children.

* Add blurb and test comment

Remove broken test of bold_toggle and test it along with its command, set_samples.
This has been incorporated into 3.6 backport PR-2796.

Use sys.modules.get() in the "with _ModuleLockManager(name):" block
to protect the dictionary key with the module lock and use an atomic
get to prevent race condition.

Remove also _bootstrap._POPULATE since it was unused
(_bootstrap_external now has its own _POPULATE object), add a new
_SENTINEL object instead.

* bpo-19896: Add typcodes 'q' and 'Q' to multiprocessing.sharedctypes. Patch by Antony Lee.

* Add NEWS entry.

* Slightly tweak NEWS entry

Make it clear this is more of a fix rather than a new feature.

Adds a new 'Pip not installed' section that covers
running `ensurepip` manually, and also references
the relevant section of the Python Packaging User
Guide.

Only C implementation was tested.

When running the test suite using --use=all / -u all, exclude tzdata
since it makes test_datetime too slow (15-20 min on some buildbots)
which then times out on some buildbots.

-u tzdata must now be enabled explicitly, -u tzdata or -u all,tzdata,
to run all test_datetime tests.

Fix also regrtest command line parser to allow passing -u
extralargefile to run test_zipfile64.

Travis CI: remove -tzdata. Replace -u all,-tzdata,-cpu with -u all,-cpu since tzdata is now excluded from -u all.

Cython will, in the right circumstances, offer a MethodType instance
where im_func is a builtin function. Any instance of MethodType is
automatically assumed to be a Python-defined function (more
specifically, a function that has an inspectable signature), but
_set_signature was still conservative in its assumptions. As a result
_set_signature would return early with None instead of a mock since
the im_func had no inspectable signature. This causes problems
deeper inside mock, as _set_signature is assumed to _always_
return a mock, and nothing checked its return value.

In similar corner cases, autospec will simply not check the spec of the
function, so _set_signature is amended to now return early with the
original, not-wrapped mock object.

Patch by Aaron Gallagher.

Patch by LouieLu.

Patch by Louie Lu.

Fix logic for retrying nuget.exe download with Python.
Add support for HOST_PYTHON variable.
Clear internal environment variables used in find_python.bat
Use HOST_PYTHON as the actual Python if it is recent enough.
Adds HOST_PYTHON variable to AppVeyor configuration

* bpo-30794: added kill() method to multiprocessing.Process

* Added entries to documentation and NEWS

* Refactored test_terminate and test_kill

* Fix SIGTERM and SIGKILL being used on Windows for the tests

* Added "versionadded" marker to the documentation

* Fix trailing whitespace in doc

* Remove obsolete fallback code in readline module

* Add NEWS

* Remove obsolete include

* Fix macro on Windows

* bpo-30450: Fall back to git.exe if no Python is found.

* Also check whether git.exe is on PATH if it will be used.

* bpo-30450: Adds alternate download approach for nuget.exe

* Whitespace fix.

* Improve signal delivery

Avoid using Py_AddPendingCall from signal handler, to avoid calling signal-unsafe functions.

* Remove unused function

* Improve comments

* Use _Py_atomic API for concurrency-sensitive signal state

* Add blurb

Updates ssl and tkinter projects to use pre-built externals