Merge branch 'feature/parametertreeconstructor' into 'master'

ref:core/dune-istl This MR Only contains the ParameterTree constructors from
MR [!85].

See merge request [!315]

  [!85]: gitlab.dune-project.org/NoneNone/merge_requests/85
  [!315]: gitlab.dune-project.org/core/dune-istl/merge_requests/315

this change became necessary to correctly manage data created in the
solver factory. We implement the following changes:

* we introduce a new constructor taking a shared_ptr<MemberType>
* all old constructors are deprecated
* we update the test and the AMG implementations to the shared_ptr and
  pass it to Hierarchy

merged commits:
* Use default values for creating AMG from ParameterTree
* Support user defined ParallelInformation in constructor with ParameterTree

Merge branch 'issue/missing_richardson_construction_traits' into 'master'

ref:core/dune-istl

### Summary

This MR adds a missing specialization of the template ConstructionTraits for
the sequential preconditioner Richardson.

### Details

Since Richardson does not provide a matrix_type, also the SmootherTraits and
DefaultConstructionArgs must be specialized.

See merge request [!304]

  [!304]: gitlab.dune-project.org/core/dune-istl/merge_requests/304

Merge branch 'feature/fix-compiler-warning-uninitialized-pamg' into 'master'

See merge request [!292]

  [!292]: Nonecore/dune-istl/merge_requests/292

Merge branch 'iterative_solver_cleanup' into 'master'

ref:core/dune-istl This MR removes duplicate code in iterative solvers by
moving

-   convergence check
-   invalid defect norm check (inf or NaN)
-   output

to a class Iteration. A instance of this class is created with
IterativeSolver::startIteration and is intended to be kept in the local scope
of the apply method. During iteration the method Iteration::step checks for
all the things mentioned above. The destructor fills all fields of
InverseOperatorResult and prints the final statistics if verbose is positive.

See merge request [!284]

  [!284]: gitlab.dune-project.org/core/dune-istl/merge_requests/284

Merge branch 'fix/ilu_documentation' into 'master'

ref:core/dune-istl The current documentation of SeqILU and SeqILUn claims,
that the parameter n is the number of iterations to perform. Actually the
parameter is passed into bilu_decomposition, which states that n is the order
of the ILU decomposition. This MR adjusts the docu on SeqILU and SeqILUn.

See merge request [!313]

  [!313]: gitlab.dune-project.org/core/dune-istl/merge_requests/313

# Conflicts:
#   dune/istl/solvers.hh

Merge branch 'add_constructors_that_take_shared_ptr_to_iterative_solvers' into 'master'

See merge request [!311]

  [!311]: Nonecore/dune-istl/merge_requests/311

Merge branch 'add_constructors_that_take_shared_ptr_to_iterative_solvers' into 'master'

ref:core/dune-istl This MR add constructors for IterativeSolvers that take
std::shared_ptr instead of references.

See merge request [!310]

  [!310]: gitlab.dune-project.org/core/dune-istl/merge_requests/310

Merge branch 'bugfix/colcomp-remove-warning' into 'master'

See merge request [!309]

  [!309]: Nonecore/dune-istl/merge_requests/309

Merge branch 'bug/document-scalarproduct-change' into 'master'

ref:core/dune-istl [!421] changed the signature of the methods dot() and
norm() in ScalarProduct, making them const. This breaks compilation of
existing user implementations, so let's document that change.

See merge request [!308]

  [!421]: gitlab.dune-project.org/NoneNone/merge_requests/421
  [!308]: gitlab.dune-project.org/core/dune-istl/merge_requests/308

!421 changed the signature of the methods `dot()` and `norm()` in
`ScalarProduct`, making them `const`. This breaks compilation of existing user
implementations, so let's document that change.

Merge branch 'unit-test-for-scalar-products' into 'master'

See merge request [!307]

  [!307]: Nonecore/dune-istl/merge_requests/307

Semantically they are const, and the current implementations
really are const too, so let's mark them in the interface
as such.

Merge branch 'issue/apply_forward' into 'master'

ref:core/dune-istl

### Summary

Implement apply<forward> for NonoverlappingBlockPreconditioner and replace
stored pointer with concrete type to allow the call to this non-virtual
function.

### Details

The method apply<forward>() is added for some preconditioners to allow to
distinguish between forward and backward application. This is not part of the
virtual interface in Preconditioner, so needs a concrete type to be called.
The function was missing in the NonoverlappingBlockPreconditioner that wraps
another preconditioner.

For both block preconditioners, the function apply<forward>() is called on the
abstract base class Preconditioner that does not have this method. So, instead
of storing a pointer to the base class, store the passed preconditioner type
directly that is available by template parameter.

### Backport

In dune 2.6 the base-class problem was not a problem, since there always the
template parameter type was stored. But the implementation in
NonoverlappingBlockPreconditioner is missing there as well. This simply breaks
generic code.

Note, the problem was introduced in [!274]. This MR is related to issue [#69].

See merge request [!302]

  [!274]: gitlab.dune-project.org/NoneNone/merge_requests/274
  [#69]: gitlab.dune-project.org/NoneNone/issues/69
  [!302]: gitlab.dune-project.org/core/dune-istl/merge_requests/302

Merge branch 'issue/missing_gs_construction_traits' into 'master'

ref:core/dune-istl

### Summary

This MR adds a missing specialization of the template ConstructionTraits for
the sequential preconditioner SeqGS.

See merge request [!303]

  [!303]: gitlab.dune-project.org/core/dune-istl/merge_requests/303

Merge branch 'feature/run-more-mpitests-in-parallel' into 'master'

See merge request [!296]

  [!296]: Nonecore/dune-istl/merge_requests/296