Refactored core

UI navigation framework

Related Work Items: #408, #414, #416

FoxTube.Core/Models/User.cs

@@ -5,12 +5,10 @@ using Google.Apis.Oauth2.v2.Data;
 using Google.Apis.Services;
 using Google.Apis.YouTube.v3;
 using Google.Apis.YouTube.v3.Data;
-using Newtonsoft.Json;
 using System;
 using System.Linq;
 using System.Collections.Generic;
 using System.Threading.Tasks;
-using Windows.Storage;
 using YouTube;
 using YoutubeExplode;
 using FoxTube.Services;
@@ -42,8 +40,6 @@ namespace FoxTube.Models
 
 				UserService.SubscriptionsChangedInvoker(this, subscription);
 				Subscriptions.Remove(subscription);
-
-				SaveSubscriptions();
 				return false;
 			}
 			else
@@ -79,21 +75,10 @@ namespace FoxTube.Models
 				Subscriptions.Add(subscription);
 
 				UserService.SubscriptionsChangedInvoker(this, subscription);
-
-				SaveSubscriptions();
 				return true;
 			}
 		}
 
-		private void SaveSubscriptions()
-		{
-			Dictionary<string, string> subs = Subscriptions.Select(i =>
-				new KeyValuePair<string, string>(i.ChannelId, i.Avatar.Default__?.Url))
-				as Dictionary<string, string>;
-
-			ApplicationData.Current.RoamingSettings.Values[$"Subscriptions.{UserInfo.Id}"] = JsonConvert.SerializeObject(subs);
-		}
-
 		public static async Task<User> GetUser(UserCredential credential)
 		{
 			User user = new User