feat: NestedScrolling behavior on complicated layouts works

[dmytroKarataiev]

Added nested scrolling behavior to the PullToRefreshView which works on complicated layouts and copies behavior of a standard SwipeRefreshLayout (on scroll down when reaches top of the screen it starts opening layout animation).

Animation logic moved to a separate method to avoid repetitive code and improve readability.

[tylersuehr7]

Thanks! This fork really helped a lot!

I have the Phoenix refresh layout as the parent to a RecyclerView which was nested inside a CoordinatorLayout with an AppBarLayout that has scroll flags set on it. The normal Phoenix refresh layout will not allow the AppBarLayout to scroll back down, but the version you created in this fork successfully does and saved me hours of time.