Changed CElement with CountryCode and fix error on favorite null

lib/country_code.dart

@@ -0,0 +1,26 @@
+mixin ToAlias {}
+
+@deprecated
+class CElement = CountryCode with ToAlias;
+
+/// Country element. This is the element that contains all the information
+class CountryCode {
+  /// the name of the country
+  String name;
+
+  /// the flag of the country
+  String flagUri;
+
+  /// the country code (IT,AF..)
+  String code;
+
+  /// the dial code (+39,+93..)
+  String dialCode;
+
+  CountryCode({this.name, this.flagUri, this.code, this.dialCode});
+
+  @override
+  String toString() => "$dialCode";
+
+  String toLongString() => "$dialCode $name";
+}