appstream 0.13.1 Tools and libraries to work with AppStream metadata

AppStream is a cross-distribution effort for enhancing the way we interact with the software repositories provided by distributions by standardizing software component metadata. It provides the foundation to build software-center applications, by providing metadata necessary for an application-centric view on package repositories. It additionally provides specifications for things like an unified software metadata database, screenshot services and various other things needed to create user-friendly application-centers for distributions.