This patch refactors (hopefully) all parts of opm-core that are needed
by the fully implicite black oil solver in opm-autodiff and that inherently
relied on UnstructuredGrid.
We added a new simple grid interface consisting out of free functions
that will allow us to use CpGrid without copying it to an UnstructuredGrid
by the means of the GridAdapter. Using this interface we have add methods that
allow specifying the grid information (global_cell, cartdims, etc.) wherever
possible to prevent introducing grid parameters for the type of the grid.
Unfortunately this was not possible everywhere.
This commit implements some additional scaling keywords. This includes
the ISWL-family that provide hysteresis behaviour via alternative
scaling of the tables. The old parser has been somewhat extended for
testing purposes. The commit also includes a slight refactoring of the
SatFunc-family where a new base class has been introduced.
