Package upgrades

- Upgraded all packages to latest version
- Removed obsolete code due to version upgrade
- More nullref warnings silenced

src/NadekoBot/Services/Impl/RedisCache.cs

@@ -24,7 +24,6 @@ namespace NadekoBot.Core.Services.Impl
 
             Redis = ConnectionMultiplexer.Connect(conf);
             _redisEndpoint = Redis.GetEndPoints().First();
-            Redis.PreserveAsyncOrder = false;
             LocalImages = new RedisImagesCache(Redis, creds);
             LocalData = new RedisLocalDataCache(Redis, creds, shardId);
             _redisKey = creds.RedisKey();