Random Tape Test failures

[MoKob]

The current test set-up exhibits a broken behaviour on Travis-CI. On some runs, we show a missing test in running npm test on the node/nepomuk directory.

The test is not failing itself but rather seems to depend on some sort of race condition, shutting down the tape test before succeeding in its execution, showing test count !== plan as error.

[MoKob]

It seems like everytime the above issue happens, we see /home/travis/build/mapbox/nepomuk/mason_packages/headers/cppzmq/4.2.1/include/zmq.hpp:444: void zmq::context_t::close(): Assertion rc == 0' failed.` thrown as an error beforehand.