Nodes - Added to float node

Nodes - Updated almost all custom VMs to stay in sync across multiple instances

src/Artemis.Core/VisualScripting/CustomNodeViewModel.cs

@@ -1,9 +1,23 @@
-using Newtonsoft.Json;
-
-namespace Artemis.Core
+namespace Artemis.Core
 {
+    /// <summary>
+    ///     Represents a custom view model for a <see cref="INode" />
+    /// </summary>
     public interface ICustomNodeViewModel
     {
+        /// <summary>
+        ///     Gets the node the view models belongs to
+        /// </summary>
         public INode Node { get; }
+
+        /// <summary>
+        ///     Called whenever the custom view model is activated
+        /// </summary>
+        void OnActivate();
+
+        /// <summary>
+        ///     Called whenever the custom view model is closed
+        /// </summary>
+        void OnDeactivate();
     }
 }