update to 1.5.23
    
    - Update translations from zanata (de, ja, pl, uk updated)
    - emoji_picker.py: Add a menu button to change the font for the emoji
    - emoji-picker: Make background colour of the flowbox listing the emoji white
    - emoji-picker: Use “Symbola” as the default font
    - Remember the font and the fontsize in a config file
    - emoji_picker.py: Add a spin button to change the font size of the emoji
    - Add option to the emoji-picker to load *all* Unicode characters
    - UI redesign of the emoji-picker
    - Return an empty list immediately if candidates() is called with an empty search string
    - Make the fontsize for the names of the emoji in the search results smaller
    - Make the search in emoji-picker a bit more responsive by using GLib.idle_add()
    - Save the recently used emoji immediately, not only when the program quits
    - Set default font size of emoji-picker to 24 instead of 16
    - Set the emoji font only for the emoji, not for its name in the search results
    - Set WM_CLASS of emoji-picker and ibus-setup-typing-booster correctly
    - Add “Icon” and “Categories” to emoji-picker.desktop