Fixes, Android adaptive icon for crypto.

lib/base/base_state.dart

@@ -50,6 +50,8 @@ abstract class BaseState<T extends StatefulWidget> extends State<T> {
   /// Возвращает контейнер с всеми виджетами экрана.
   Widget getScreenContent();
 
+  bool isAutomaticallyImplyLeading();
+
   /// Возвращает заголовок для AppBar
   String getTitle() {
     return null;
@@ -59,6 +61,7 @@ abstract class BaseState<T extends StatefulWidget> extends State<T> {
     return new AppBar(title: new Container(
         margin: new EdgeInsets.only(left: 16.0),
         child: new Text(getTitle(), style: new TextStyle(fontSize: 18.0))),
+        automaticallyImplyLeading: isAutomaticallyImplyLeading(),
         backgroundColor: Resources.getPrimaryColor(app),  actions: getMenuButtons());
   }
 

lib/screens/currencies.dart

@@ -17,6 +17,7 @@ class _CurrenciesState extends SettingsBaseState<CurrenciesScreen> {
 
   _CurrenciesState(SqliteHelper helper, String app) : super(helper, app);
 
+  bool isAutomaticallyImplyLeading() => true;
 
   @override
   List<String> getOptions() {

lib/screens/faq.dart

@@ -22,6 +22,8 @@ class EntryItem extends StatelessWidget {
   const EntryItem(this.entry);
   final Entry entry;
 
+  bool isAutomaticallyImplyLeading() => true;
+
   Widget _buildTiles(BuildContext context, Entry root) {
     EdgeInsets margin = new EdgeInsets.only(left: 20.0, right: 20.0);
     TextStyle titleStyle = Theme.of(context).textTheme.button.copyWith(

lib/screens/finish_registration.dart

@@ -24,6 +24,8 @@ class RegistrationScreenState extends BaseState<FinishRegistrationScreen> {
   bool _tokenActive = false;
   String _merchantID = '';
 
+  bool isAutomaticallyImplyLeading() => false;
+
   @override Widget build(BuildContext context) {
     if (_merchantID == '') {
       helper.getMerchantID().then((result) {

lib/screens/languages.dart

@@ -18,6 +18,8 @@ class LanguagesState extends SettingsBaseState<LanguagesScreen> {
 
   List<String> languages = const ['ru', 'en', 'ua', 'es'];
 
+  bool isAutomaticallyImplyLeading() => true;
+
   @override
   List<String> getOptions() {
 

lib/screens/purchase.dart

@@ -37,6 +37,8 @@ class PurchaseScreenState<T> extends BaseState<PurchaseScreen> {
   FocusNode _focusNodeSum = new FocusNode();
   FocusNode _focusNodeBonus = new FocusNode();
 
+  bool isAutomaticallyImplyLeading() => false;
+
   PurchaseScreenState(SqliteHelper helper, String app, String userString, String card) : super(helper, app) {
     this.user = JSON.decode(userString);
     this.card = card;

lib/screens/purchase_success.dart

@@ -41,6 +41,8 @@ class PurchaseSuccessScreenState<T> extends BaseState<PurchaseSuccessScreen> {
   int currency;
   bool showBonus;
 
+  bool isAutomaticallyImplyLeading() => false;
+
   @override String getTitle() {
     return StringsLocalization.carryingPurchase();
   }

lib/screens/registration.dart

@@ -25,6 +25,8 @@ class RegistrationScreenState extends BaseState<RegistrationScreen> {
   RegistrationScreenState(SqliteHelper helper, String app) : super(helper, app);
   FocusNode _focusNode = new FocusNode();
 
+  bool isAutomaticallyImplyLeading() => false;
+
   @override
   Widget build(BuildContext ctx) {
     return getMainWidget();

lib/screens/settings.dart

@@ -36,6 +36,8 @@ class SettingsState extends BaseState<SettingsScreen> {
 
   bool returnToScanner;
 
+  bool isAutomaticallyImplyLeading() => true;
+
   SettingsState(SqliteHelper helper, String app, bool returnToScanner) : super(helper, app) {
     this.returnToScanner = returnToScanner;
   }

lib/screens/splash.dart

@@ -30,6 +30,8 @@ class _SplashScreenState extends BaseState<SplashScreen> {
   _SplashScreenState(SqliteHelper helper, String app) : super(helper, app);
   bool a = false;
 
+  bool isAutomaticallyImplyLeading() => false;
+
   @override
   void initState() {