Support Flat and Outline type.
README version update.
Resolved Bug: Avoid a animate=false scenario that setState is called after dispose.
Resolved Bug: Avoid a scenario that dispose is called on a null AnimationController.
Improves package health.
Support Customized content widgets. Support auto adjusts board radius. Add examples.
Implement basic progress button function and animation.
Use onProgress
call back onPressed and returns a result handler function to indicate animation is completed and you are ready to go.