[h2oair] Use sqrt instead of pow to speedup viscosity evaluation

test_stokes2c with refined grid speeds up by 2.7%.

See merge request !192

test_stokes2c with refined grid speeds up by 2.7%.

Feature/scotch matrix reordering

Reordering the matrix leads to improved sparsity pattern. This is especially important for growing network grids.

Reordering results using the ReorderingDofMapper implemented by this MR with a growing network grid.

* Original unsorted FoamGrid
![original](/uploads/4f29ec169127ea67dbe814f6ee9daab5/original.png)
* Reordered dof indices
![reordered](/uploads/e2ade49c081353981b00cdf8ce7b2c51/reordered.png)


See merge request !186

The mapper computes a permutation of the index set using the external PT-SCOTCH library.
This is a simple replacement for element mapper (cc) / vertex mapper (box). It requires to
store on int per dof for the mapping (fast direct vector access).
This makes the matrix bandwidth small and reduces the fillins during LU factorization.
So it helps especially for direct solvers or iterative solver preconditions by ILU.
The reordering is particularly helpful for network problems with foamgrid to optimize
the matrix sparsity pattern.

This enables the use of Dune's single codim single geometry mapper
that otherwise exists failing a static assert

[2p2c] Improve Millington&Quirk and constant tau

A quick test (Clang 3.8, one run, no error bar) of test_box2p2c with the optim.ops from dumux and a 100 times finer grid:  
Millington&Quirk: 99 s  
Constant Tau: 95 s  
That's about 5%. But more measurements are required and the differences in the solution must be checked.

This merge request does not address all changes proposed in the task [FS#321](http://www.dumux.org/flyspray/index.php?do=details&task_id=321)

See merge request !181

* Reduce number of template arguments
* Rename property from tau to TauTortuosity

Use multiplications and a cubic root instead
of std::pow
* Estimated 5% less time in 2p2c computation
* Roughly inbetween old code and constant tau

[fix][test] Fix the reference solution name for 2pbox fracture. We start counting from 0 now.



See merge request !190

[box/fvelementgeometry] Implement prism elements

* computeGeometries() worked for tetrahedrons and hexahedrons.

See FS#324

See merge request !161

Fix/fs309 uninitialised values

- [x] Move plotoverline2d.hh from dumux/io to test/porousmediaflow/mpnc/implicit


See merge request !176

[fracturebox2p] Add forgotten reference vtu file



See merge request !187

Feature/discrete fracture 2d3d test for box

Make box work for discrete fracture network grids 2d in 3d

*  [x] Fix scvf normal computation 2d in 3d
*  [ ] Fix boundary?

See merge request !172

Feature/new 3pwateroil



See merge request !179

Merge branch 'feature/new-3pwateroil' of https://git.iws.uni-stuttgart.de/dumux-repositories/dumux into feature/new-3pwateroil

Conflicts:
	test/porousmediumflow/3pwateroil/implicit/3pwateroilsagdproblem.hh

Holger Class authored Jul 26, 2016 and Bernd Flemisch committed Aug 18, 2016

lecture. Unlike there, we use here a non-zero capillary pressure to use
rel-perms and capillary pressures from dumux stable

Holger Class authored Jul 26, 2016 and Bernd Flemisch committed Aug 18, 2016

This was previously already available locally in dumux-lecture.

[gstat][doc] Add peer-reviewed paper as reference



See merge request !184

[cornerpoint] adapt to current Opm release 2016.04

With Opm release 2016.04, the module dune-cornerpoint has been
renamed to opm-grid. Interfaces changed without deprecation. There
doesn't seem to be a preprocessor macro to check for the employed
Opm version. Therefore, drop support for older versions and only
support 2016.04.

See merge request !182

[gridcreator] Fix gmsh grids for parallel alugrid runs

Dune-alugrid needs the gmsh reader to only fill the grid factory on rank 0.
See mergerequest !14 https://gitlab.dune-project.org/core/dune-grid/merge_requests/14.
This is different e.g. for UG that needs the grid on all processes.

See merge request !183

Dune-alugrid needs the gmsh reader to only fill the grid factory on rank 0.
See mergerequest !14 https://gitlab.dune-project.org/core/dune-grid/merge_requests/14.
This is different e.g. for UG that needs the grid on all processes.

remove superfluous `Dumux::` qualifiers

Everything in our .hh files is defined within the namespace `Dumux`.
There were numerous occurrences of `Dumux::` qualifiers that were
unnecessary. Remove those occurrences. Necessary qualifications
remain, such as `typedef Dumux::H2O<Scalar> H2O;`.

See merge request !178

The installexternal.sh script can be used to install opm
and ert and to apply patches to opm-common and opm-parser.

With Opm release 2016.04, the module dune-cornerpoint has been
renamed to opm-grid. Interfaces changed without deprecation. There
doesn't seem to be a preprocessor macro to check for the employed
Opm version. Therefore, drop support for older versions and only
support 2016.04.

* Vector was accessed out of range

lecture. Unlike there, we use here a non-zero capillary pressure to use
rel-perms and capillary pressures from dumux stable

This was previously already available locally in dumux-lecture.

Everything in our .hh files is defined within the namespace `Dumux`.
There were numerous occurrences of `Dumux::` qualifiers that were
unnecessary. Remove those occurrences. Necessary qualifications
remain, such as `typedef Dumux::H2O<Scalar> H2O;`.