add missing ParMETIS flags to pamg_comm_repart_test

See merge request core/dune-istl!404

[ci] add configuration with DUNE_ISTL_WITH_CHECKING

Closes #72

See merge request core/dune-istl!403

[scalarproduct] Add constructor taking a shared_ptr<const Comm>

See merge request core/dune-istl!383

Use modern CMake for FindSuperLU

See merge request core/dune-istl!397

With SuperLU 5.0 version macros are provided.

Call find_path, find_library only one due to changed semantics
Drop undocumented SUPERLU_PREFIX and SUPERLU_ROOT, CMake uses
SuperLU_ROOT by default now.

make storeMatrixMarket able to choose the decimal precision

See merge request core/dune-istl!400

Merge branch 'set_decimal_precision' of https://gitlab.dune-project.org/core/dune-istl into set_decimal_precision

Fetch default yml files via different project instead of url

See merge request core/dune-istl!398

This is a workaround for a bug that showed up after gitlab migration. See issue
infrastructure/issues0#62 for further discussion.

Merge branch 'cleanup/fix-compiler-warnings' into 'master'

See merge request [core/dune-istl!394]

  [core/dune-istl!394]: Nonecore/dune-istl/merge_requests/394

This reverts commit 0385deac.

Merge branch 'cleanup/remove-deprecated-solvecategory-interface' into 'master'

See merge request [core/dune-istl!390]

  [core/dune-istl!390]: Nonecore/dune-istl/merge_requests/390

Merge branch 'am2cmake' into 'master'

ref:core/dune-istl\> The last bits in dune-common were removed in
[dune-common!719].

See merge request [core/dune-istl!388]

  [dune-common!719]: gitlab.dune-project.org/Nonedune-common/merge_requests/719
  [core/dune-istl!388]: gitlab.dune-project.org/core/dune-istl/merge_requests/388

The last bits in dune-common were removed in dune-common!719.

Merge branch 'feature/require-cmake-3.13' into 'master'

See merge request [core/dune-istl!387]

  [core/dune-istl!387]: Nonecore/dune-istl/merge_requests/387

Merge branch 'feature/fix-broken-macro-guard' into 'master'

ref:core/dune-istl\> The loaction of the macro guard lead to the method test
not returning a value if neiter SUperLU nore SuiteSparse are found. While the
test is not executed in this case due to a CMake guard, these macro guards
should be placed in the correct place anyways for reasons of code hygiene.

See merge request [core/dune-istl!385]

  [core/dune-istl!385]: gitlab.dune-project.org/core/dune-istl/merge_requests/385

The loaction of the macro guard lead to the method `test`
not returning a value if neiter SUperLU nore SuiteSparse
are found. While the test is not executed in this case due
to a CMake guard, these macro guards should be placed
in the correct place anyways for reasons of code hygiene.