Merge branch 'issue/update_changes_from_feature_branch' into 'develop'

some changes from feature/block_matrix adopted

See merge request !19
1 job for develop in 2 minutes and 32 seconds (queued for 1 second)
Status Name Job ID Coverage
failed dune:git--gcc #5728


Name Stage Failure
dune:git--gcc Test
CMakeFiles/Makefile2:1768: recipe for target 'test/CMakeFiles/TreeDataTest.dir/all' failed
make[2]: *** [test/CMakeFiles/TreeDataTest.dir/all] Error 2
CMakeFiles/Makefile2:213: recipe for target 'CMakeFiles/build_tests.dir/rule' failed
make[1]: *** [CMakeFiles/build_tests.dir/rule] Error 2
Makefile:247: recipe for target 'build_tests' failed
make: *** [build_tests] Error 2
--- Failed to build amdis ---
Terminating dunecontrol due to previous errors!
ERROR: Job failed: exit code 1