[common.localization-study] renamed run_localization() -> run()
[fem.femeoc] fixed unsafe integer conversion
[functions.flattop] added first draft to playground
[test.function] added base FunctionTest to derive from
[test.functions_flattop] added test
[functions.flattop] moved out of playground, tests succeed
[functions.default] added matrix valued VisualizationAdapter

By printing the scalar frobenius norm of the matrix.
[playground.grid.provider.starcd] fix range of logical not (!)
Merge branch 'master' of https://github.com/wwu-numerik/dune-stuff
[function.interfaces] mark copy() as deprecated

Did not make much sense in the end, Rene was right after all^^
[common.memory] added ConstStorageProvider
[functions.interfaces] reorderen includes
[functions.interfaces] do not guard dune-geometry usage
[functions.combined] complete rewrite

There is now a generic combined function and the combination action can be
defined by specializing a small internal class. The old Difference is now
implemented as a derived class.
[functions.combined] added Sum
[functions.combined] added dimensions for sum
[functions.interfaces] added operator+
Merge branch 'master' of https://github.com/wwu-numerik/dune-stuff