Fred, Jamie, Stefan

I was asked to install an "observation intend" bit that will be included in the interferometer state vector (ODC master). For now this is only intended to report that the IMC is ready.

What I did:
- Updated masks for the guardian input to ODC -right now there are only two bits: operator intent and guardian intend. The keep-alive is currently not used.
- Updated the IMC guardian to turn on its bit when it is done locking the IMC, and turn it off when it detects a lock loss.
- Added a user button on the Guardian main screen to report the operator intent (snap short).

With this, the H1 ODC master (H1:ODC-MASTER_CHANNEL_OUT_DQ) reports when the mode cleaner is locked, Guardian thinks so too, and a human being set the operator intent bit (or forgot to unset it...).

Obviously it will only be as good as the commissioners using it.