kconfig: Move flavours into their own subdirectories.

* Split out non-generic Makefile targets into new Makefiles.
* Each flavour has its own specific Makefile now.
* Rename lxdialog to menuconfig.
* Update POTFILES.in

Signed-off-by: David Graeff <david.graeff@web.de>
kconfig: Add qconfig makefile target additionally to the xconfig target

Because we no longer only target the xserver with the qt frontend of kconfig
and due to the name beeing inconsistent with the other makefile targets
an additional qconfig target is added.

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

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.

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>