trivial: Fix up a few log messages
Make appending an XML header optional
Sanitize the XML more when reading cdata
Add some more warnings if applications are non-awesome
Update the published version of the AppData spec
Use cra_app_set_icon_type() to be clear
Save XML formatted localized descriptions

This currently trips up gnome-software, but it's the format we've decided with
the AppStream upstream maintainer.
Add <releases> support
Add the start of font plugin