MatrixMarket for GMPField and Float128

See merge request !436

Add flags to tests explicitly

See merge request !509

fix incorrect comment in ilu.hh

See merge request !606

The order of the multiplication is wrong, important for block elements

[doc] Add missing changelog entry for FastAMG changes

See merge request !605

Check that output indices are stored

See merge request !604

Fix memory leak in the CHOLMOD wrapper code

See merge request !602

When calling CHOLMOD to compute the Cholesky factor of a matrix,
it was not tested whether such a factor already existed. As a
consequence, if the solver was called twice in a row, the old
factor would be lost to a memory leak.

Fix this by explicitly deallocating the old Cholesky factor
before asking CHOLMOD for a new one.

Make FastAMG work with non-blocked matrices

See merge request !600

Use fixed seed instead of clock value to make results of
blocked and non-blocked version and results of different
test runs comparable.

[umfpack] Add support for Dune::Matrix

See merge request !586

The internal operations of `FastAMG` assumed that the entries
of the matrix are vectors are matrices and vectors themselves
by making use of the dune matrix and vector interfaces. As a
consequence `FastAMG` cannot be used with `BCRSMatrix<double>`
in contrast to `BCRSMatrix<FieldMatrix<double,1,1>>`.

This patch introduces `IsNumber`-based switches in the respective
places that use plain arithmetic operators if the matrix/vector
is not blocked thus adds the missing support for e.g. `BCRSMatrix<double>`.

Set up default include directories on module target

See merge request !598

Make multirhstest compile and run

See merge request !596

[Bugfix] calling invert on zero matrix

See merge request !599

Remove the CI job with checking

See merge request !594