Delete stamp-vc

See merge request !1857

[cleanup] Use if constexpr to replace SFINAE

See merge request !1858

[test][material][components] added new components needed for the biomin example

See merge request !1855

There seems to be no point in having this. It's pretty easy to find out if you have a git repository or a tarball

[darcystokes] Remove velocity output from reference solution

See merge request !1853

[test][darcystokes] Disable velocity output

See merge request !1852

The velocity output (post-processing)
is not very exact and makes it hard to compare
the results to a reference solution.

Fix/test 2ptracer vangenuchten

See merge request !1851

[vangenuchten] Introduce pore-connectivity parameter L

See merge request !1807

Gabi Seitz authored Jan 29, 2020 and Timo Koch committed Jan 31, 2020

cornerpoint test is missing

* Use l in krw/krn instead of hard-coded l=0.5
* Correct the non-wetting relperm to comply with the Mualem model
* Correct the non-wetting relperm derivative

The parameter is used in the relative permeability curve in the Mualem model.
Mualem (1976) suggested that 0.5 is a good value for many soils. Sometimes a
value different from 0.5 is provided, which is why this patch implements it as additional variable.

[bugfix] Komega and LowReKepsilon typetags for the ransnc tests were switched

See merge request !1849

Feature/cleanup parallel solvers

See merge request !1848

* use specializations of VectorCommDataHandle instead

* createIndexSetAndProjectForAMG -> createParallelIndexSet
* getExtendedMatrix -> extendMatrix

[cppstandard] Require C++17

Closes #654

See merge request !1824