Release 1.15.0 "Feedback loop"

This release adds new layouts, and new types of layout, plus fixes a regular allotment of bugs, and improvs the internal design a whole lot.

Here are the changes that you might notice without digging into code.

Layouts:

• Arabic layout from Khaled Eldoheiri
• Swiss French from Jordi
• Bulgarian from Plamen Stoev
• Swiss German from Patrick Jörg
• Armenian from Norayr Chilingarian
• Wide French terminal from Arnaud Ferraris
• PIN layout

Improvements:

• Integration into GNOME translations
• A debug mode that starts the GTK inspector
• Better errors when can't start
• Better docs (thanks PhilProg)

Bug fixes:

• Unblurred icons
• Not showing on the lock screen for no reason
• Theme changes without restarting now
• Input hint can take effect without having to refocus the field