Support for Opera Mini

Opera Mini and some other mobile browsers use servers to process JavaScript, then send the result back to the device. Devices like these don't support the Scroll event, so I added a check to the constructor that verifies the browser supports 'onscroll'. If it doesn't, we won't hide the manual pagination link. This allows the plugin to fail gracefully on low-power mobile devices.

I've only been able to test this with Opera Mini for iOS, so verification that it works on other devices/browsers would be appreciated.