Add Hive wallet to bitcoin.org

Live preview: http://bitcoinhive.us.to/en/choose-your-wallet

As suggested in #293, Hive seems like a good Bitcoin client candidate to be displayed on bitcoin.org . v1.0 is out now and we could wait for v1.1 before merging this pull request. Hive supports encryption and backups and user feedback seems pretty good since the launch of the beta versions.

This pull requests also adds Hive to the list of open-source projects and translatable projects.