Sync game details (fixes #90)

It's all functional, the release year and the icons get updated after the game entry has been updated on the website. 

And I added removal of unpublished && uninstalled games to cleanup existing libraries filled with many unpublished steam games. This piece of code is meant to live for only one version.

~~There's an annoying bug that I need to track down though. I get a GTK freeze after that a bunch of unpublished games have been auto-removed.~~