Dmedia 12.12

* Dmedia now does full content hash verification with a 2 week threshold; the first time you run 12.12, you might notice a lot of CPU and disk activity as none of the files in your library will have been verified; later we'll add smarter scheduling and throttling (avoid verifying while on battery power, don't verify when other apps are taxing the system, etc)

* Dmedia now does automatic durability downgrading based on hard-coded thresholds: 2 days for files that have never been verified; 7 days since the last time a FileStore was connected; 28 days since a file was last verified

* The doc.atime is now updated when Dmedia.Resolve() is called (atime update is lazy and asynchronous to get around previous performance issues)

* Schema change: the per-location mtime in doc.stored is now truncated to an int (was a high-precision floating point timestamp)

* The MetaStore class now has complete test coverage

* dmedia-service can now at least start when org.gnome.SessionManager isn't available (although it will be lacking session management)

* For extra safety as we work on validating Dmedia for production readiness, dmedia-service now snapshots all the databases before it starts replication or the active monitoring tasks