Regular updates

Some of the entries here seem to be quite old.
Checking on a regular basis for updates could keep all the apps up to date.
Travis allows you to create "cron-jobs".

Idea: (github repos)
- Extend the data format to contain optional meta information on the last release tag.
- Check "all" / random portion of projects daily if new releases have been made
- Automatically create update pull-requests for new tags.