Fix handle leak in Windows for Java >= 10

[effad]

As discussed in https://github.com/profesorfalken/jProcesses/issues/32, there is a handle leak when using WM4Java for Java versions beyond 10. This PR works around the problem by explicetly closing the streams of process.

Here's a Test that can be executed to demonstrate the problem:

    public void testWindowsHandleLeak() {
    	JProcesses jprocesses = JProcesses.get().fastMode();
    	for (int i = 0; i < 1000; i++) {
    		jprocesses.listProcesses();
    		System.gc();
    		System.out.println("#" + i);
    	}    	
    }

when run one can see in the task manager that the handles of the javaw executable go up all the time. After the fix is applied, handle count stays stable.