language: Emit locale changed signal only after everything else

This signal is used to rebuild all pages and they might want to check
the current language during initialization so we should only emit it
after we set everything.

https://bugzilla.gnome.org/show_bug.cgi?id=736763
keyboard: Remove dead code

This is already done a few lines earlier.

https://bugzilla.gnome.org/show_bug.cgi?id=736764
keyboard: Disregard the current locale when adding IBus engines

Similarly to 198e3bbb080109188d21482214ca829ecbd19628 we should
include all the relevant IBus engines.

https://bugzilla.gnome.org/show_bug.cgi?id=736764
keyboard: Add the default input source regardless of type

Some locales suggest an IBus engine as default input source. We should
add it to the list and if we haven't been able to fetch the engine
descriptions from IBus yet we use the id as label. Note that as soon
as we connect to IBus and get the descriptions we'll update the label,
see update_ibus_active_sources() .

https://bugzilla.gnome.org/show_bug.cgi?id=736764
keyboard: Ellipsize input source labels

Some input sources have unreasonably long labels which might make us
too wide. Ellipsize them.

https://bugzilla.gnome.org/show_bug.cgi?id=736764
refine spacing

Refine vertical spacing as a part of ongoing
layout work.

https://bugzilla.gnome.org/show_bug.cgi?id=734808
timezone: Vertically center the title

With the image now hidden, the title needs to be centered.

https://bugzilla.gnome.org/show_bug.cgi?id=734808
goa: Fix alignment of subtitle

As this is a multi-line subtitle, it should be left-aligned with
the list below it. Make it so.

https://bugzilla.gnome.org/show_bug.cgi?id=734808