v2.0 beta-1 (formerly v1.3 beta-1) - for internal testing

• Major internal rewrite for maintainability + reliability
• New: Modnotes implementation (fixes #7)
• New: Spotlight queue management feature
• New: Refactor of all command UI and usability improvements
• New: Admin-only, mod-channel-only and admin-channel-only check constraints
• Fix: Various commands were restricted to mod channels
• Fix: dice commands will reject unexpected commands
• Fix: if config.json (main config file) does not exist, the displayed error is not useful
• Fix: Improved logging facilities
• Fix: Various minor bugfixes - see git history