[priVarSwitchNewtonController] Make work again with volVar caching on

Closes #432

See merge request !746

Kilian Weishaupt authored 7 years ago and Timo Koch committed 7 years ago

* fvGeometry, fluxVar and volVar caching
* compare against solution with caching off

Feature/linearsolver multitype matrix

Closes #435

See merge request !744

* Specialize solve depending on whether
  MultiTypeMatrices are accepted by the solver or not

[test] Make backward compatible with dune 2.5

See merge request !750

Fix/compilation

See merge request !749

[navierstokes] Clean-up indentantation in fluxVars

See merge request !747

Feature/improve bboxtree

See merge request !748

In case one dimension is very small take the maximum between the to be tested box dimensions
in the corresponding axis direction. There is one corner case left where the epsilon is very small:
If there are two bboxes of lines, both parallel in an axis direction, their collision is only
detected if the coordinates are an exact match. However, we currently do not see any used case
where this might occur.

[seq][bugfix] Fix par solver construction, AMG has now a default constr too but for only sequential runs.

Make FVGridGeometry independent of TypeTag

See merge request !742