Switch configuration logic from a custom structure to
fully rely on MidoriWebSettings. This includes revamping
the preferences dialog. The old logic is not yet
replaced completely, this will follow soon, thus several
settings will have no effect right now.
Based on the implementation of localization via Gettext
contributed by Enrico Tröger, a few adjustments were made
to allow Midori to be properly localized. Initially
German is fully supported.
