[AL] Move switch-case into element loop.

This results in fastest (in number of read instructions) code.
Add missing include.
[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.
Merge branch 'GWPLocalAsm' into develop
[PL] Add initialize debug message.
[PL] Add simple GWFprocess::post() writing result.
[PL] Add next steps for solve().
[PL] Add GlobalSetup as template to GW process.

Enable parsing of processes' configs, now the types are correct.
[PL] Add global matrix and rhs/solution vectors.
Add LinearSolver to GWProcess.
GW: Make linear solver happy with identity matrix.
[PL] GW: Add vector of local assemblers.
[PL] GW: Add local assembler initialization.
[PL] Add global assembler to GroundwaterFlowProcess.
[PL] Execute global assembler on local assemblers.
[PL] Pass  GlobalMatrix/Vector types to local assembler.