In addition to replacing the imp module code with the suggested replacements, this PR also:
Removes use of pkg_resources (also deprecated)
Removes the last use of six
Removes the last use of __future__
Cleaned up some other code that produced out of date import statements; basically, we're never going to run Pandokia on Python 2 again, so we don't need those if statements.
tweaks the code in setup.py that sets the version to still produce valid version numbers even though we're now including version-mission in our tags.
In addition to replacing the imp module code with the suggested replacements, this PR also:
__future__See also PR https://github.com/spacetelescope/pandeia_test/pull/1741 and https://github.com/spacetelescope/steuermann/pull/7