New settings screen - clock & transport source priority

[RadekPilich]

This would be useful for setups, where you don't always power up all your gear. 

The setting screen should provide ordered list of 3-5  selectable inputs, that would be cross-checked at all times (or by some refresh soft button action) and only the clock and transport from the highest active input would be passed through to the routings.

The clocks and transport messages from the other inputs on the list would be filtered out.

[RadekPilich]

This request was based on lack of understanding how clock works on MRCC.

However I would still like, if this was possible, so that it would work like this:
- passing clock and transport from all inputs would be blocked
- however there would be a possibility to have MRCC internal generator to listen for clock and transport on selected inputs and use those to set it's internal clock and trigger it's internal transport and then distribute those to mapped outputs (while swallowing the inputs)