Added DiscordShardedClient, some DiscordSocketClient fixes.

src/Discord.Net.WebSocket/Commands/ShardedCommandContext.cs

@@ -0,0 +1,31 @@
+using Discord.WebSocket;
+
+namespace Discord.Commands
+{
+    public class ShardedCommandContext : ICommandContext
+    {
+        public DiscordShardedClient Client { get; }
+        public SocketGuild Guild { get; }
+        public ISocketMessageChannel Channel { get; }
+        public SocketUser User { get; }
+        public SocketUserMessage Message { get; }
+
+        public bool IsPrivate => Channel is IPrivateChannel;
+
+        public ShardedCommandContext(DiscordShardedClient client, SocketUserMessage msg)
+        {
+            Client = client;
+            Guild = (msg.Channel as SocketGuildChannel)?.Guild;
+            Channel = msg.Channel;
+            User = msg.Author;
+            Message = msg;
+        }
+
+        //ICommandContext
+        IDiscordClient ICommandContext.Client => Client;
+        IGuild ICommandContext.Guild => Guild;
+        IMessageChannel ICommandContext.Channel => Channel;
+        IUser ICommandContext.User => User;
+        IUserMessage ICommandContext.Message => Message;
+    }
+}