kconfig: Update/Port Gtk flavour to use Gtk3

* Use only non-deprecated functions, use accessor functions instead of
    direct access.
* libglade is deprecated: use GtkBuilder and ui files instead.
* Remove some global variables.
* Use new gtk signals.
* Split code into gconf.c and gconf_treeview_model. gconf.c now
    only contains ui init and ui signal callback code, all tree/model
    code is in the second file.
* Use more icons from the system theme instead of the lowres
    images.c constants.
* Update POTFILES.in

Signed-off-by: David Graeff <david.graeff@web.de>
kconfig: Qt interface port to Qt4/Qt5, removed Qt3 Support

* Use Qt designer ui file instead of handwritten ui code
* Use Qt Model/View design
* Qt5 compatibility
* Makefile adopted: Add uic (Qt interface compiler) support.
* Set organisation and application name for QApplication/QSettings.
* Update POTFILES.in

Signed-off-by: David Graeff <david.graeff@web.de>
kconfig: images.c for gtk/qt gui flavour reoganized

Change order of xpm image constants to build up groups.
Make those groups optional via ifdefs.
Remove not used constants.

Signed-off-by: David Graeff <david.graeff@web.de>