Moved event stuff to a non-manager NS.

Core assembly concept: Assemblies that will never need to get unloaded (Torch.API, Torch, Torch.Server)
Event shims and patch shims on the core assemblies.

Torch.API/Event/EventHandlerAttribute.cs

@@ -0,0 +1,28 @@
+using System;
+
+namespace Torch.API.Event
+{
+    /// <summary>
+    /// Attribute indicating that a method should be invoked when the event occurs.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Method)]
+    public class EventHandlerAttribute : Attribute
+    {
+        /// <summary>
+        /// Events are executed from low priority to high priority.
+        /// </summary>
+        /// <remarks>
+        /// While this may seem unintuitive this gives the high priority events the final say on changing/canceling events.
+        /// </remarks>
+        public int Priority { get; set; } = 0;
+
+        /// <summary>
+        /// Specifies if this handler should ignore a consumed event.
+        /// </summary>
+        /// <remarks>
+        /// If <see cref="SkipCancelled"/> is <em>true</em> and the event is cancelled by a lower priority handler this handler won't be invoked.
+        /// </remarks>
+        /// <seealso cref="IEvent.Cancelled"/>
+        public bool SkipCancelled { get; set; } = false;
+    }
+}