Scripting - Core implementation (#629)

Scripting - Added plugin classes
Layers - Fix certain blend modes not working as intended
UI - Add customizable header per page
Profile editor - Hide the regular header
Profile editor - Added a new toolbar

src/Artemis.UI.Shared/Plugins/ScriptingProviders/ScriptEditorViewModel.cs

@@ -0,0 +1,20 @@
+using Artemis.Core.ScriptingProviders;
+using Stylet;
+
+namespace Artemis.UI.Shared.ScriptingProviders
+{
+    /// <summary>
+    ///     Represents a Stylet view model containing a script editor
+    /// </summary>
+    public class ScriptEditorViewModelViewModel : Screen, IScriptEditorViewModel
+    {
+        /// <inheritdoc />
+        public ScriptEditorViewModelViewModel(Script script)
+        {
+            Script = script;
+        }
+
+        /// <inheritdoc />
+        public Script Script { get; }
+    }
+}