Remove some more expired ports:

devel/py-backports.functools_lru_cache
devel/py-backports_abc
devel/py-futures
devel/py-singledispatch
devel/py-typing
graphics/py-pillow6

Adjust dependent ports.
Tested with 'make index' against r559975

Revert r559792 to unbreak INDEX and bulk -a
It seems a lot of reverse dependencies were missed

With hat:	portmgr

Remove most expired ports that depend on Python 2.7:

Exceptions are:
- mail/mailman, our listservers still use it
- www/chromium, solely because of popular demand,
  upstream is (slowly) working on porting it to Python 3
- ports that have actual patches for Python 3 against
  them (Cinnamon and a few unrelated other ports)
- llvm70 and qt5-webengine because they seem to have a lot
  of dependencies which need further analysis
- sysutils/uefi-edk2-bhyve because bhyve seems to use them
- python2 and python27 themselves

I'm sure there will be complaints, but the nice thing about
a version control system is that we can revert and adjust things.

devel/py-futures: Update to 3.3.0

Changelog:

  https://github.com/agronholm/pythonfutures/blob/3.3.0/CHANGES.rst

Reported by:	ngie
MFH:		2020Q2 (blanket: bugfix release)

Clean up USES

With hat:	portmgr

devel/py-futures: Update to 3.2.0

- Update COMMENT to match upstream change

Changelog:

  https://github.com/agronholm/pythonfutures/blob/3.2.0/CHANGES.rst

PR:		226540
Submitted by:	sunpoet

devel/py-futures: Update to 3.1.1

 * Update LICENSE (PSFL)

Changelog:

  https://github.com/agronholm/pythonfutures/blob/3.1.1/CHANGES

devel/py-futures: Update to 3.0.5

- Update PORTVERSION and distinfo checksum (3.0.5)
- Correctly limit to Python versions < 3. :2 means depend on
  lang/python2 (for the python2 symlink), which is an incorrect
  specification.
- Enable NO_ARCH (architecture independent)
- Add a comment above the test target to inform our future
  selves to increase the number of POSIX semaphores using sysctl.
  FreeBSD currently defaults to 30, and I don't believe there's a
  "blessed" way to have tests run as root to do this programatically.

  Without increasing the value, many tests are skipped:

    skipped 'system provides too few semaphores (30 available, 256 necessary)'

Changes:

  https://github.com/agronholm/pythonfutures/blob/3.0.5/CHANGES

devel/py-futures: Update to 3.0.3

- Update to 3.0.3 [1]
- Add LICENSE_FILE
- Sort USE_PYTHON
- Add regression-test target for QA
- Update pkg-descr WWW: URL

Changes:

  https://github.com/agronholm/pythonfutures/blob/3.0.3/CHANGES

Based on:

PR:		201068 [1]
Submitted by:	Gasol Wu <gasol dot wu gmail com> [1]

- Convert ports of devel/ to USES=python

Approved by:	portmgr (implicit)

Update consumers of lang/python31 or higher to use Python version 3.X
and consumers of lang/python31 or lower to use Python 2.X

This is in preparation of removing lang/python31 which expired on 2014-06-01

While here apply some fixes for textproc/codespell:
- USE_XZ -> USES=tar:xz
- remove unneeded USE_PYTHON_RUN line

Approved by:	python (mva)

devel/py-futures: Update to 2.1.6 & modernise

- Update to 2.1.6
- Update LICENSE (BSD2CLAUSE)
- Deprecate easy_install target

Changes: 2.1.6 - 2013-01-14

 - Fixed a problem with files missing from the source distribution

devel/py-futures: [NEW PORT] Backport of Python 3.2 concurrent.futures module

The concurrent.futures module provides a high-level interface for
asynchronously executing callables.

This is described in PEP-3148 and is included in Python 3.2+

WWW: http://code.google.com/p/pythonfutures/