- Implemented real-time state notification using OSC-UDP.

Commit sponsored by Boffins Technologies.

Notes:
  - Based on similar functionality in  CasparCG 2.1.
  - Note not all events/messages from 2.1 are implemented.

Changes w.r.t CasparCG 2.1:
  - Better performance.
  - Use UDP instead of TCP.
  - Configurable in casparcg.config.
  - Use "Microsoft Asynchronous Agents Message Blocks" API (included in VS2010+), instead of custom "reactive" solution.