Added possibility to choose facing camera on start.

Moved the size listener to plugin side.

example/lib/main.dart

@@ -16,7 +16,6 @@ class QRViewExample extends StatefulWidget {
 }
 
 class _QRViewExampleState extends State<QRViewExample> {
-
   Barcode result;
   QRViewController controller;
   final GlobalKey qrKey = GlobalKey(debugLabel: 'QR');

lib/src/types/barcode.dart

@@ -13,4 +13,4 @@ class Barcode {
 
   /// Raw bytes are only supported by Android.
   final List<int> rawBytes;
-}
+}

lib/src/types/barcode_format.dart

@@ -56,13 +56,10 @@ extension BarcodeTypesExtension on BarcodeFormat {
     return index;
   }
 
-  BarcodeFormat fromString(String format) {
-
-  }
+  BarcodeFormat fromString(String format) {}
 
   String get formatName {
     switch (this) {
-
       case BarcodeFormat.aztec:
         return 'AZTEC';
         break;
@@ -117,5 +114,4 @@ extension BarcodeTypesExtension on BarcodeFormat {
     }
     return 'NOT_VALID';
   }
-
-}
+}

lib/src/types/camera.dart

@@ -4,4 +4,4 @@ enum CameraFacing {
 
   /// Shows front facing camera.
   front
-}
+}

lib/src/types/camera_exception.dart

@@ -11,4 +11,4 @@ class CameraException implements Exception {
 
   @override
   String toString() => 'CameraException($code, $description)';
-}
+}

lib/src/types/features.dart

@@ -10,4 +10,4 @@ class SystemFeatures {
   final bool hasFlash;
   final bool hasFrontCamera;
   final bool hasBackCamera;
-}
+}