[NumLib] Set shape matrices explicitly to zero.

This fixes some tests that are using the Eigen matrices.
[NumLib] Tests: Ensure zero entries in matrices.
[AL] Add SimpleAssembler used for shape matrix initialization.

No local vectors/matrices and no modification of global vector/matrix.
Add SimpleTest/FemTests to global cmake.
Add SimpleGroundWaterFlow cmake config.
[2dGWFlow] Add test program body that includes reading of mesh and geo.
Using read fem conditions generating mesh node ids.
Add MeshSubset.
WIP: Added some code for assembling.
Adding element constants (DIM and NPOINTS) as static variables to ShapeQuad4.
Renamed vector mesh_node_ids -> bc_mesh_node_ids.
Added includes for assembly.
Implement LocalGWAssembler.
Reduce debug output (commenting).
Add dynamic size eigen matrices types for testing.
Destroy vec_comp_dis at end of program.
Add a LIS global matrix version parallel to DenseMatrix.
Add preprocessor switch LIS/DenseMatrix.
Store bc values in vector and applying to lin eq.
Removed unnecessary matrix in LocalGWAssembler.