backdrop 0.2.6

Backdrop implementaion in dart. (https://material.io/design/components/backdrop.html)

[0.2.6] - 18 December 2018

• updated README.md

[0.2.0] - 18 December 2018

• NavigationBackLayer widget - for easily implement navigation with backdrop
• stickyFrontLayer - dynamic height for backdrop - based on height of backLayer
• animationCurve for backdrop can be passed as parameter
• minor bug fixes

[0.1.0] - 28 July 2018.

• opacity fixes in BackdropScaffold.
• headerHeight option added in BackdropScaffold.
• frontLayerBorderRadius option added in BackdropScaffold
• refactor: body -> frontLayer
• refactor: backpanel -> backLayer
• BackdropToggleButton widget implemented.

[0.0.1] - 21 July 2018.

• Basic backdrop implementation.
• BackdropScaffold widget implemented.