Lots of code refactoring to use XAML behaviors instead of code-behind

New Save button in the AppBar
EntryPage now uses the same AppBar as GroupPage (but not shared...)
Some new Symbol mappings

ModernKeePass/ViewModels/MainVm.cs

@@ -1,5 +1,6 @@
 using System.Collections.ObjectModel;
 using System.Linq;
+using Windows.ApplicationModel;
 using Windows.Storage.AccessCache;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
@@ -13,6 +14,8 @@ namespace ModernKeePass.ViewModels
         private IOrderedEnumerable<IGrouping<int, MainMenuItemVm>> _mainMenuItems;
         private MainMenuItemVm _selectedItem;
 
+        public string Name { get; } = Package.Current.DisplayName;
+
         public IOrderedEnumerable<IGrouping<int, MainMenuItemVm>> MainMenuItems
         {
             get { return _mainMenuItems; }