Add momentum scrolling support

[rustyx]

Please add momentum scrolling support, it's a de-facto scrolling feature in modern web applications.

[bumbu]

Now you can simulate this using something similar to pan animate demo.
Animated zoom looks nice, but it has a performance cost - so it could be a toggleable option.

[ghost]

Is there an example of this using easing?

[bumbu]

@simonmacfadyen no, there is no, but you could see how easing is implemented in other libraries and use that

[ghost]

@bumbu fair enough, I will take a look :)