balloon_widget 0.2.0

Provide a simple balloon widget that can be placed widget tree

0.2.0

• Add: Balloon.shadow property, BalloonShadow interface, and MaterialBalloonShadow, CustomBalloonShadow concrete class.
• [Breaking] remove Balloon.elevation and Balloon.shadowColor properties. (Use Balloon.shadow instead)
• Chore: add some API descriptions.

0.1.0

• Add BalloonNipPosition.topCenter, BalloonNipPosition.bottomCenter (PR: #4)
• Add: PositionedBalloon Widget API (PR:#6)
• Fix: fix incorrect height layout when including nip height (nip radius value difference from zero nip radius apply at nip height)

0.0.1

• initial release.