Modify the way of initialization, now more general

Support for custom Toast animation and animation duration😉

The meaning of the closeFunc parameter of the showEnhancedWidget method has changed. Now it is wait for the closeFunc function to complete before removing Toast.

Add the showAnimationWidget method, you can use this method to highly customize an animated Toast🤩

Remove the reInit method and the two deprecated enumerations PreferDirection.Below and PreferDirection.Upside

WrapWidget type method parameter changed (not compatible with 1.x version),see 1.x version upgrade 2.x version

showXxxNotification Add dismissDirections parameter

showXxxText, showXxxLoading, showXxxNotification method adds align parameter

Fixed some bugs in the showAttachedWidget method

Support flutter web (note that it cannot ensure its stability)

Updated the style of example and added more demos