[AppStream] AppStream 0.9.3 released!

[Matthias Klumpp]

A few bugfixes and a few features this time, nothing too exciting.
Most of the spec additions will come with the next release.

As always, tarballs can be found at
http://www.freedesktop.org/software/appstream/releases

Version 0.9.3
~~~~~~~~~~~~~~
Released: 2016-03-24

Features:
 * Allow to update an existing component with fresh metadata
 * Implement YAML serialization
 * writer: Allow to omit writing a header/root node
 * cli: Add convenience method to install metainfo files
 * cli: Add a new "status" command for various diagnostic information
 * yaml: Allow unicode
 * Print prettier XML by default
 * l10n: Update

Bugfixes:
 * Reset umask before building the data cache
 * apt: Work around APT using server mtime for its downloaded files