Add new feature.

Added ILogger;
Added IGraphProcessor;

Changed return type of OnExecute method in BaseNode from void to bool;

Runtime/Contracts/IGraphProcessor.cs

@@ -1,9 +1,16 @@
-namespace Misaki.GraphView
+
+using System.Collections.ObjectModel;
+
+namespace Misaki.GraphView
 {
     public interface IGraphProcessor
     {
+        public bool IsRunning { get; }
+        
         public void UpdateComputeOrder();
         
-        public void Execute();
+        public void Execute(ReadOnlyCollection<BaseNode> nodes);
+        
+        public void Break();
     }
 }