[AppStream] appstream-glib 0.7.3

[Richard Hughes]

New Features:
 - Add AS_VERSION_PARSE_FLAG_USE_BCD when formatting version strings
(Richard Hughes)
 - Add as_app_get_release_by_version() (Richard Hughes)
 - Add as_app_get_screenshot_default() (Richard Hughes)
 - Add new launchable types (Marius Vollmer, Richard Hughes)

Bugfixes:
 - Do not assign "flatpak" as an app's origin when no origin was found
(Joaquim Rocha)
 - Fix the inode mode to be sane on extracted files (Richard Hughes)
 - Prefer /usr/share/metainfo as default path for metainfo files (Jeremy Bicha)
 - Write XML for newer AppStream specification versions (Richard Hughes)

Richard.