support older versions of jquery (such as the version that ships w/ FarCry 6.3.x, v1.6.4)

By using `.click()` instead of `.on()` we can support some older versions of jQuery.  Out of the box this plugin doesn't work with FarCry 6.3.x because it uses jQuery 1.6.4.  `.on()` wasn't introduced until v1.7.