Use Lib.systemsleep in control loop

src/utilities.jl

@@ -23,7 +23,7 @@ macro periodically(h, simulation, body)
 		local start_time = time()
 		$(esc(body))
 		local execution_time = time()-start_time
-		$(esc(simulation)) || sleep(max(0,$(esc(h))-execution_time))
+		$(esc(simulation)) || Libc.systemsleep(max(0,$(esc(h))-execution_time))
 	end
 end