1) Add the possibility for the user to chose between local and global
coordinate permeability in the transmissibility calculations.
2) Trow for CpGrid
3) Add default for switch
GCC 4.8 provides 'nullptr' in C++11 mode. That capability is
detected at configuration time and stored in <config.h> and we need
it when targeting Dune 2.2.1 to avoid diagnostics of the form
[...]/dune/common/nullptr.hh:27:1:
error: expected ‘;’ after class definition
} nullptr = {}; // and whose name is nullptr
^
[...]/dune/common/nullptr.hh:27:1:
error: qualifiers can only be specified for objects and functions
[...]/dune/common/nullptr.hh:27:3:
error: expected unqualified-id before ‘nullptr’
} nullptr = {}; // and whose name is nullptr
