Removes all of the from __future__ imports that open and close the
brackets on the same line. This is most of them.

Also updated class_maker.py

Fixes all flake8 3.7.9 warnings as part of the Python 2->3 transition.

This commit replaces all header guards in tools with #pragma once.

Updates the Sanitizers to handle whitespace anywhere in the selected
sanitizer mode
Fixes an issue where undefined sanitizer would not work (generator
expressions do not handle whitespace)
Updates documentation following some feedback, and drops some old
information (such as min CMake version)

Fix indentation and suppress all Python warnings

Reverts the indentation changes introduced in an earlier commit by auto
formatting tools. Changes the regex for the address suppressions so we
match Python 2 and 3

Updates CXXTest to inject the environment required for sanitizers rather
than forcing the user to do it themselves

re #25456

Refs #16578

- Remove bind1st/bind2nd usage.
- Avoids an internal compiler error in gcc with getProperty.
- Adds wrapper around sip executable to process the output and
  remove the throw specifiers. They are not allowed in C++ 17.
Refs #26261

These supported the no longer used Git workflow, hence are no longer
needed.

Updates the generator script and introduces minor layout changes.