Using the noSlip boundary condition for rotating wall in an MRF region
interferes with post-processing by resetting the wall velocity to 0 rather than
preserving the value set by the MRF zone.
so that the specification of the name and dimensions are optional in property dictionaries.
Update tutorials so that the name of the dimensionedScalar property is
no longer duplicated but optional dimensions are still provided and are
checked on read.