Upgrade setuptools.depends to importlib from depracated imp

Fix code for detecting Visual Studio's version on Windows under Python 2.

pkg_resources: fix ``Requirement`` hash/equality implementation

Document using asterisk in package_data section

docs: drop ez_setup documentation and related references

doc: drop most references to EasyInstall

Add Python 3.8 final to Travis test matrix

Fixes for python3.10

Improve Visual C++ 14.X support

Document support for Python 3.8 through a trove classifier

Remove outdated comment and suppressed exception from test_test.py

The test command has not called sys.exit since commit
2c4fd432.

Change coding cookie to use utf-8 (lowercase)

Deprecate the test command

Provide a warning to users. Suggest using tox as an alternative generic
entry point.

Refs #1684