Interactable component system. (#9)

* InteractableComponent v1. Broken edition

* It works!

Content.Server/Interfaces/GameObjects/Components/Interactable/IInteractableComponent.cs

@@ -0,0 +1,48 @@
+using SS14.Shared.Interfaces.GameObjects;
+using System;
+
+namespace Content.Server.Interfaces.GameObjects
+{
+    public interface IInteractableComponent : IComponent
+    {
+        /// <summary>
+        ///     Invoked when an entity is clicked with an empty hand.
+        /// </summary>
+        event EventHandler<AttackHandEventArgs> OnAttackHand;
+
+        /// <summary>
+        /// Invoked when an entity is clicked with an item.
+        /// </summary>
+        event EventHandler<AttackByEventArgs> OnAttackBy;
+    }
+
+    public class AttackByEventArgs : EventArgs
+    {
+        public readonly IEntity Target;
+        public readonly IEntity User;
+        public readonly IItemComponent Item;
+        public readonly string HandIndex;
+
+        public AttackByEventArgs(IEntity target, IEntity user, IItemComponent item, string handIndex)
+        {
+            Target = target;
+            User = user;
+            Item = item;
+            HandIndex = handIndex;
+        }
+    }
+
+    public class AttackHandEventArgs : EventArgs
+    {
+        public readonly IEntity Target;
+        public readonly IEntity User;
+        public readonly string HandIndex;
+
+        public AttackHandEventArgs(IEntity target, IEntity user, string handIndex)
+        {
+            Target = target;
+            User = user;
+            HandIndex = handIndex;
+        }
+    }
+}