Improve scrolling performance with passive event listeners about ng2-idle

[moribvndvs]

Implemented in a5e24eb. However, this has to be manually enabled by your application, and should do so based on whether or not you detect the browser supports this feature (since not all will).

I did not want to build feature detection into this module as it is out of scope, but instead leave that up to you. However, I've added a function that you can use in concert with the feature detection of your choice so you can still utilize default interrupt sources. More info here.

Simply change to the following (this example uses detectIt):

const idle = new Idle();
idle.setInterrupts(createDefaultInterruptSources({passive: detectIt.passiveEvents});
idle.watch();