[AL] Add back addToGlobal() in VectorMatrixAsm.
[T] Add GlobalMatrix/Vector to SteadyDiffusion2D example.
[PL] GW: Add LocalAssemblerData skeleton.
[PL] GW: Fill init, assemble. Add shape matrices.
[AL] 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: Store hydraulic conductivity in each elem.

This shall be changed later to incorporate different
material properties.
[PL] GW: Rename LocalAssemblerDataBase to Interface.

Same change in the AssemblerLib for consistency.
[PL] GW: Shorten shape_matrix names.
[PL] Move initialization of local mat/vec to init.

This also changes the locas assembler builder.
The test is updated.
[NL] Add shape matrix reinitialization.

Used for dynamic size matrices and there
is almost no overhead for fixed size matrices.
[NL] Add commented dynamic matrix policy.
Correct number of integration points. Dynamic order.

This corrects a bug in calculation of integration points number.
Other changes allow a user to specify the integration order at runtime at
initialization of the local assemblers.
[AL] Correct template names adding _ suffix.
[AL] Improve documentation.
[PL] GW: Correct member variables' names.
[PL] GW: Add noalias() for local matrix operation.
[PL] GW: Missing includes in FEM.h.
[PL] GW: correct type of n_integration_points.
Merge pull request #521 from endJunction/GWPLocalAsm

Local assembler for GroundwaterFlowProcess and LocalDataInitializer