DOC
FIX: avoid unterminating loop when generating dense graphs without parallel edges
FIX: test name. FIX: make sure m <= n(n-1) for all tests

So that tests don't require multigraphs
run tests on graphs without paralell edges by default
compiler flag -fno-omit-frame-pointer is only required for debugging
REF: rename
Generation of multi-graphs has to be enabled explixitly