This commit introduces a new top-level "manager" for all saturation
function consistency checks. This component associates collections
of saturation function curves with per-cell or per-region end-point
definitions and provides an interface to run all checks for all
interior entities (i.e., active cells) in a DUNE grid view. We form
one set of SatfuncConsistencyChecks objects for each
SatfuncCheckPointInterface<> object, thereby enabling running the
same set of consistency checks for both the unscaled, tabulated,
per-region saturation functions and the per-cell scaled saturation
functions. The latter is executed only if the run enables end-point
scaling for the saturation functions while the former is executed
only if the run does not enable end-point scaling.
At present we're limited to reversible and non-directional
saturation functions for the drainage process only, but those
restrictions will be lifted in due time.
As an aid to enabling the pertinent individual checks, we add a
private factory function which considers the run's active phases and
whether or not the run uses the alternative, three-point horizontal
scaling method ("SCALECRS = YES").
