Quire Server 0.2.0

What's Changed

• The server updates itself: checked first, backed up, rolled back by itself by @dpoposki in #5
• Sites update themselves every night, and Quire's signed feed is checked by @dpoposki in #6
• Sites build on Quire's runtime images only when they check out by @dpoposki in #7
• Backups off the server: every night, encrypted, kept and checked by @dpoposki in #8
• Sites are built again on a newer runtime, every night by @dpoposki in #9

Full Changelog: v0.1.1...v0.2.0