* -Wshorten-64-to-32
* -Wmismatched-tags
* -Woverloaded-virtual
* -Wfloat-equal
* -Wnon-virtual-dtor

* -Wunreachable-code
* -Wcovered-switch-default
* -Wswitch-enum
* -Wunused-const-variable
* -Wunused-private-field

This allows a 1x1 matrix to be constructed from a 1d vector

* added -Wlogical-op-parentheses to clang
* added -Wundef to clang

Clang does not know this feature.

This reverts commit 342c6e5d660afc0fe1488fc2701b3cce010a3025.

This reverts commit 847555675db1dba6cd6c5d5d9afccf2211f4d124.

There should be a fix in our dune-fem.

* ensure dune-commons cmake stuff is used only with --use-cmake

* give mpi info in parallel runs
* overwrite DUNE_THROW

This reverts commit 6f96536ef3a8385f08341abc7786116aa489c273.

@ftalbrecht move this anywhere you like please

* mainly provides an additional operator*