Fixed Crash in MobileGridDateColumn

Fixed broken Caching in CoreRepository

InABox.Mobile/InABox.Mobile.Shared/Components/MobileGrid/MobileGridDateColumn.cs

@@ -19,7 +19,7 @@ namespace InABox.Mobile
 
         public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
         {
-            throw new NotImplementedException();
+            return value;
         }
         
         public String Format { get; set; }

InABox.Mobile/InABox.Mobile.Shared/DataModels/CoreRepository.cs

@@ -549,7 +549,7 @@ namespace InABox.Mobile
             var data = storage.WriteBinary(BinarySerializationSettings.Latest);
             try
             {
-                var file = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), FileName);
+                var file = CacheFileName(FileName);
                 File.WriteAllBytes(file,data);
             }
             catch (Exception e)