Properly shutdown clojure after it ends
Properly shutdown clojure after it ends

In order to make the integrations tests not exit after each one,
I removed the java call to exit the program after clojush finishes.

however, then it wouldn't stop when threads were still open, so we
add this call to stop all threads and then clojush will exit properly
again

thelmuth/Clojush,NicMcPhee/Clojush,saulshanabrook/Clojush,lspector/Clojush,lspector/Clojush,Vaguery/Clojush,Vaguery/Clojush,NicMcPhee/Clojush,thelmuth/Clojush,saulshanabrook/Clojush