Remove async call in close Swift

Avoid null pointer exception after webview is disposed

Remove headers_build_phase from example's Podfile

Fix crash on xcode 10.2

add new option to control the contentMode in Android platform

Fixes #106

Adds a transparentBackground option for iOS and Android

The 'open' method requires an options dictionary

iOS: Call setNeedsLayout() in scrollViewDidScroll()

This is useful to prevent a brief white flash on initialization
for apps that use a dark theme.

Otherwise, SwiftFlutterPlugin.swift throws an exception on line 285
when the InAppBrowser.openWithSystemBrowser(url) method is called:

  let options = (arguments["options"] as? [String: Any])!

Otherwise, the web view scrolls in blank white space which
doesn't get painted until the scroll gesture is finished,
because the WKWebView hasn't rendered that part of the
viewport to its offscreen buffer.

Add null checks around calls to InAppWebView callbacks

This prevents a crash I've been seeing as of v1.1.2 (for the onScrollChanged callback)
and should also prevent any other similar possible crashes.

Also, suppress an unused_field analyzer warning for InAppWebViewController._id.

fix #74, merge #81 #83, fix javascript `...args` parameter of `window.flutter_inappbrowser.callHandler()`

bug fix for android build

Enable setTextZoom function of Android-WebViewSetting

Android dependency 'androidx.core:core' has different version for the compile (1.0.0) and runtime (1.0.1) classpath

 Enable setTextZoom function of Android-WebViewSetting

updated documentation for addJavaScriptHandler method, updated README.md, updated inline webview example

added return value for JavaScriptHandlerCallback, added flutterInAppBrowserPlatformReady event for javascript, breaking change: javaScriptHandlersMap contains only one callback

upgrade to androidX