Initial split of the modules

NadekoBot.Core/Common/ModuleBehaviors/IEarlyBlockingExecutor.cs

@@ -0,0 +1,18 @@
+using System.Threading.Tasks;
+using Discord;
+using Discord.WebSocket;
+
+namespace NadekoBot.Common.ModuleBehaviors
+{
+    /// <summary>
+    /// Implemented by modules which can execute something and prevent further commands from being executed.
+    /// </summary>
+    public interface IEarlyBlockingExecutor
+    {
+        /// <summary>
+        /// Try to execute some logic within some module's service.
+        /// </summary>
+        /// <returns>Whether it should block other command executions after it.</returns>
+        Task<bool> TryExecuteEarly(DiscordSocketClient client, IGuild guild, IUserMessage msg);
+    }
+}