Handle UEV_HUP properly in examples and unit tests

If an I/O watcher callback fails to read(), returning zero, we check
events for UEV_HUP to detect EOF or socket remote end shutdown().

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

examples/redirect.c

@@ -35,7 +35,7 @@ void process_stdin(uev_t *w, void *arg, int events)
 		return;
 	}
 
-	if (len == 0) {
+	if (len == 0 || UEV_HUP == events) {
 		warnx("Connection closed.");
 		return;
 	}