Merge branch 'hotfix/0.4.7.2'
Portability improvements

* Added "Utils.getOS" as a nicer interface to check the OS name and
  use it all around.

* Added support for the output variant of ldd on NetBSD, not braces
  there.

* Don't use Linux specific linker options with non-Linux like NetBSD,
  not needed and not working there.
NetBSD: Disable the standalone mode tests while they cannot possibly work.
FreeBSD: Fixups for clang

* At least in debug mode, it insists on a newline on the last line,
  so add it.

* Don't set debug option not supported on FreeBSD.
FreeBSD: Determine the program directory without optional procfs.
Cleanup node tree checking and statements building

* No more overloads of "setChild" to mutate values when they get updated,
  make "checkers" a generic method for that.

* This avoids inconsistencies as to when these checkers are executed,
  which wasn't consistently done.

* Merge statement sequences within re-formulations more directly, so as
  to avoid that as noise during optimization.

* Being "discard" method of nodes, which shall be called when nodes
  become unused. Not active yet.

* Lots of style cleanups
Standalone Tests: Prepare addition of PyQt based test, enhanced module presence check.

* The check for module presence was using the Python of the runner
  instead of the Python to be used, therefore giving false results
  potentially.

* Making the module presence check a function is cleaner and more
  reusable too.
More changelog work.
Cleanup, move statement sequence processing into the respective nodes.

* This cleanup leads to leaner constraint collection code, and is
  intended to make abstract execution more self contained.

* Also many style cleanups
Cleanups only

* Format function and class definitions with no spaces for braces.

* PyLint cleanups
Show inclusion of compiled modules as well
Standalone: Added support for implicit imports of PyQt4.QtCore

* Not configurable mechanism so far.

* Hopefully not needed that often.
Cleanup, don't use children having base class when the interface is not to be used.
Debian: Added script used to create and upload Nuitka repositories
Tests: Make runners executable with Python3.
Python3: Allow early loaded modules to be extension modules.

* Happens on least on Gentoo.

* Non-optional extension modules make no sense of course.
Standalone Tests: Added test case for PyQt.
Release: Refined Debian package and OSC upload scripts.
New pre-release.
Release: Minor cleanups to debian release script

* Also avoid spurious output from changelog check.

* Accept if directories already exist.