[Bf-codereview] Paths and Windows Installer Fixes (issue4529081)

[brechtvanlommel at gmail.com]

Reviewers: bf-codereview_blender.org,

Description:
This patch attempts to address windows installer and
script/configuration file path issues. In particular:

* Addon scripts not getting installed in the correct location.
* Windows installer not working for non-administrator users or multiple
users.

They are related, and need to be fixed simultaneously to avoid breakage.
The fundamental issue I think is that system files and configuration
files are mixed up. The windows installer is writing system files to the
configuration directory, and user defined scripts and configuration are
sometimes written to system directories.

The available paths are in my opinion ambiguous, so I've removed some
and for others, mostly the change has been to get user paths before
local paths. For the windows installer, scripts and other datafiles are
now always installed next to the executable, there is no longer an
option for their install location.

One big remaining issue is that of compatibility with existing files
installed in AppData (i.e. system files written to a configuration
directory). For a new 2.58 version the scripts directory could not get
copied over from 2.57 to avoid the problem, but it also needs to work in
the meantime.

This is a work in progress, patch is not ready yet, still need to test
it on more configurations and platforms, only did initial testing on mac
and windows. But feedback is welcome.

Please review this at http://codereview.appspot.com/4529081/

Affected files:
   build_files/scons/tools/btools.py
   release/windows/installer/00.sconsblender.nsi
   source/blender/blenfont/intern/blf_lang.c
   source/blender/blenlib/BLI_path_util.h
   source/blender/blenlib/intern/path_util.c
   source/blender/editors/space_file/space_file.c
   source/blender/python/intern/bpy.c
   source/blender/python/intern/bpy_interface.c
   source/blender/windowmanager/intern/wm_files.c
   source/creator/creator.c
   source/gameengine/Ketsji/KX_PythonInit.cpp