Tests: Allow frame objects and assignments from constants as optimization results.
Python3: Fixup test version checks
Debian: Place the ReST source files in /usr/share/doc/nuitka as well.
Quote arguments given to Scons

* Just in case filenames might contain spaces.
Developer Manual: Describe the Nuitka Logo in the manual as well.
Python3: Install scons only if not already installed.
Refine special handling of unknown encoding errors.

The special handling of Debian including patches for newer error message
has been made more general, as everything else is not having it.
RPM: Follow the standard description used for Debian as well.
Use Nuitka fonts in documentation headers.

This does not yet force embedding of fonts into the PDF, but it makes sure
the official PDFs will have them.
Refactor optimization of temp keeper variables to be based on SSA analysis

* From tests it appears that no change to the generated XML dumps is
  achieved. This is so far only about doing an existing optimization
  that was done with dead end code with SSA based code.

* Version temp keeper assignments as well and trace references in the
  SSA state.

* Removed obsolete variables handling retained from value friends now
  and merge only branches of conditional statements with SSA states.

* Optimize temp keeper references based on SSA variable trace up to
  then, instead of via value friend code.

* Variable reference handling cleanups to provide saner interface.

* Make locals built-in use each local variable, and only those, so it does
  not block temp keeper variables, but makes sure local variables are used
  by calls to it.

* Make temp keeper exception raising from assign source immediately
  visible for more direct optimization.

* Remove value friend classes that make no sense anymore and became or
  were unused.

* Apply SSA analysis to modules as well, was only functions before.
Cleanup, remove value friends from SSA assignment trace.

* Was added without point, value friends should go away.
Cleanup, remove the last traces of value friends, all choices can be based on nodes instead.
Changelog updates
New pre-release.