RectDrawer Interactive Animate.

Opt CircleDrawer.kt

Opt IndicatorView

update gradle version.

Opt indicator animation after page switch

Support indicator animation after page switch

update viewpagerindicator version

Fix #30,null cannot be cast to non-null type kotlin.Int

Fix getIndicatorGap

Fix #25 indicate the unit of setSliderWidth()

Add license in library class.

Opt demo code and RectDrawer.

Update README_CN.md

Update README.md

Update README_CN.md