No cancelIdleCallback support

[julienR2]

When use in framework context with component life cycle, you usually want to make sure to cancel all the listener and callback that could have affected your component once unmounted.

However this polyfill doesn't implement the cancelIdleCallback which can lead to errors like window.cancelIdleCallback(..) is not a function on browsers not supporting ric

I made a PR to add this support to the current polyfill https://github.com/PixelsCommander/requestIdleCallback-polyfill/pull/4