add vibrate and alarm functions

samples/alarm-sample.lua

@@ -0,0 +1,11 @@
+function on_resume()
+    ui:show_lines({ "Vibrate", "Alarm" })
+end
+
+function on_click(idx)
+    if idx == 1 then
+        system:vibrate(500)
+    else
+        system:alarm_sound(5)
+    end
+end