Fix launching from gnome-shell

Instead of starting in headless mode, start in the interactive mode and
bring up the UI when we're being DBus activated.

To make this possible, this patch separates the GSettings loading and
command line parsing, so we would only have to parse the command line
when started on the command line, and skip this in the DBus activation
case.

https://bugzilla.gnome.org/show_bug.cgi?id=735375
Present the existing window when activated in UI mode

https://bugzilla.gnome.org/show_bug.cgi?id=735375
Start command line instances in non-unique mode

This makes it possible to run non-interactive command line instances in
parallel to an existing UI instance. Activating the app from the
.desktop file launcher or starting with --interactive still brings up
the same, unique window.

https://bugzilla.gnome.org/show_bug.cgi?id=735375
Updated Korean translation