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After rebasing, the tests failed due to 0ccde397
that had been introduced on master.

* Store less information in contexts
* Move projection methods to manager
* Minor cleanup

* Store coupling facets only once
* Store indices of coupling facets of scvfs
* Introduce facet iterator

The implemented BJ test used an indefinite permeability matrix
which lead to loss of convergence.
The new test is according to Cao et al.

The implemented BJ test used an indefinite permeability matrix
which lead to loss of convergence.
The new test is according to Cao et al.