GW: Make linear solver happy with identity matrix.
Update ShapeMatrixPolicy.

This avoids template template parameter.
for PR: Specify full path in includes.
md GroundwaterFlowFEM.h
md hydraulic conductivity
[NL] Add DIM, NPOINTS to all ShapeFunction classes.

The expressions are needed for local assembler matrix sizes.
[PL] GW: Add LocalDataInitializer.

This adds a mapping from element types to the
corresponding shape functions. The latter are
passed as a template parameter to the
LocalAssemblerData.
[PL] GW: Add local assembler initialization.
md Move local_assemblers to private section.
[ML] Add compile-time evaluated pow() function.

Used in computation of integration points' number
at compile time depending on the mesh element's
spatial dimension.
[PL] GW: Add IntegrationPolicy and order to LAsm.
[PL] GW: Add IntegrationPolicy, order to LDataInit.
[PL] GW: Pass integration types from process to LA.
WIP. Mainly Eigen matrices in shape_matrices array.