kconfig: finer customization via popup menus

This allows to configure every symbol list and info window separately via a
popup menu, these settings are also separately saved and restored.  Cleanup
the ConfigSettings class a bit to reduce the number of #ifdef.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>