Merge branch 'develop-pre-release' of develop.openfoam.com:Development/OpenFOAM-plus into develop-pre-release

Fields now correspond to the initial residual for the first solver
iteration

Residual fields can be written using the new 'writeFields' entry, e.g.

    functions
    {
        residual
        {
            type            residuals;
            libs            ("libutilityFunctionObjects.so");
            fields          (".*");
            writeControl    writeTime;
            writeFields     true;
        }
    }

Fields currently correspond to the initial residual for the last solver
iteration.

-dry-run : perform check only and no writing
-dry-run-write: perform check and write to the next time step.  This
also triggers function objects that fire on the call to write()

- this is consistent with compiler defaults, and helps Darwin users