1. Migrate to AndroidX
2. Fix nestedScrollingChild who is designed for horizontal can't scroll vertically by gesture

Optimize scroll

1. Fix scroll issue when parent is not a NestedScrollingParent
2. Fix the content view's height

Allow missing navigation view.

Optimize fling

Use TYPE_NON_TOUCH instead of fling

Fix measure issue

1. Measure nav view too
2. Make stickyNavLayout open

Fix that StickyNestedLayout performs error when child view has margins

fix #8