Fixed issue with Horizontal list not refreshing. Added clientId to joinPartyResponse. Crashing on multiple user joins.

Aurora/Models/PartyMember.cs

@@ -0,0 +1,22 @@
+using System;
+
+namespace Aurora.Proto.Party
+{
+    /// <summary>
+    /// Partial PartyMember class with a constructor that generates a new id
+    /// </summary>
+    public partial class PartyMember
+    {
+        public PartyMember(string id)
+        {
+            if (!string.IsNullOrWhiteSpace(id))
+            {
+                Id = id;
+            }
+            else
+            {
+                Id = Guid.NewGuid().ToString();
+            }
+        }
+    }
+}