fix pichillilorenzo#43, fix pichillilorenzo#73

fix pichillilorenzo#98, fix pichillilorenzo#93, fix pichillilorenzo#80

merge pichillilorenzo#85

fix pichillilorenzo#74, merge pichillilorenzo#81 pichillilorenzo#83, …

…fix javascript `...args` parameter of `window.flutter_inappbrowser.callHandler()`

updated README.md

fix pichillilorenzo#56, some code cleanup

added support for AndroidX, version 1.0.0

updated CHANGELOG.md