Reduced data in .dat/.bin files

We want the .dat/.bin files not to be overly large, as they currently are. There are two possible approaches:

 1. Select output on a variable basis, as we do for the Moorings
 2. Select output groups (prognostics, diagnostics, forcings)

We've already implemented parts of option 2, as we can turn of/on diagnostics and forcings output - but prognostics are always output.