[ML] Remove size check, because eigen has no getNRows()

Maybe we should choose different interface instead.
[PL] GW: Add global assembler.
[PL] GW: Execute global assembler on local assemblers.
[PL] GW: Add debug messages in init, solve, post.
[PL] Add mesh node ids for BoundaryCondition.
[PL] Initialize node ids vec in boundary conditions.
[PL] Add simple GWFprocess::post() writing result.
GW: Make linear solver happy with identity matrix.
debug A.
mu Commented materials.