[java] Make java Threads follow how cpp/neko implement them, and let them be killed as the program exits

std/java/vm/Thread.hx

@@ -85,5 +85,6 @@ private class HaxeThread extends java.lang.Thread
 		super();
 		threadObject = hxThread;
 		runFunction = run;
+		setDaemon(true);
 	}
 }