Exchange troubled cell

See merge request !15

more reasonable.

Merge branch 'feature/exchange-troubled-cell' of ssh://gitlab.dune-project.org:22022/dune-fem/dune-fem-dg into feature/exchange-troubled-cell

DGPyOperator.

interpolation quadratures.

scaled function to the solution.

it is also used for normal limiter

of the physicallity check. In 'patch.py' the 'physicalBounds' is not being
added anymore to the 'physical' method and its construction can be removed
at a later stage

Merge branch 'feature/exchange-troubled-cell' of ssh://gitlab.dune-project.org:22022/dune-fem/dune-fem-dg into feature/exchange-troubled-cell

This does reduce the accuracy slightly but also the 'noise'

Merge branch 'feature/exchange-troubled-cell' of ssh://gitlab.dune-project.org:22022/dune-fem/dune-fem-dg into feature/exchange-troubled-cell

reconstruction.

holds quadrature types and default quadrature orders.

run.