* consider sum of distances within inside and outside element

Feature/pass fluxcache to neumann

Closes #660

See merge request !1626

Bugfix/assembly numdiff explicit

See merge request !1707

This was previously not possible because of the bug in the
explicit/numdiff assembler. The large epsilon masked the error
in the storage derivative. Now it also works with small epsilon.

[facet][box] do not use support points for coupling fluxes

See merge request !1688

This reverts changes introduced in
aa5951f5 and the following commits.
It turned out that doing the flux computation on the basis of a support
point inside the cell and then a tpfa flux towards the facet elements
performed very bad for anisotropic tensors.

Use entity.type() instead of creating a temporary geometry

See merge request !1686

Constructing a geometry may be expensive depending on the grid
implementation.

[readme] Fix coverage link

See merge request !1685

Feature/add hint to disable prop macro warning

See merge request !1679

[cleanup] Replace depr prop macros by GetPropType traits

See merge request !1678

[readme] Add coverage info

See merge request !1681

[cmake][test] Increase timeout to be able to test in debug mode

See merge request !1680

[stokesdarcy][couplingdata] Fix deprecation warning

See merge request !1677

[staggered][scvf] Adapt geometry and corner storage

See merge request !1546

Update README.md with doc section

See merge request !1676

Cleanup/poromechanics

See merge request !1675

[io][vtkfunction] return copy of shared ptr

See merge request !1674

Feature/gmsh boundary flag for alugrid

See merge request !1672