added drawFunc property to layer so that layers can easily draw non-node background graphics

src/Layer.js

@@ -18,6 +18,7 @@ Kinetic.Layer = function(config) {
     this.lastDrawTime = 0;
     this.beforeDrawFunc = undefined;
     this.afterDrawFunc = undefined;
+    this.drawFunc = undefined;
 
     this.canvas = document.createElement('canvas');
     this.context = this.canvas.getContext('2d');
@@ -142,6 +143,12 @@ Kinetic.Layer.prototype = {
 
         this.clear();
         if(this.attrs.visible) {
+        	// draw custom func
+        	if (this.drawFunc !== undefined) {
+        		this.drawFunc();	
+        	}
+        	
+        	// draw children
             this._drawChildren();
         }
 

src/Shape.js

@@ -23,7 +23,7 @@ Kinetic.Shape = function(config) {
         lineJoin: undefined,
         detectionType: 'path',
         shadowColor: undefined,
-        shadowBlur: undefined,
+        shadowBlur: 5,
         shadowOffset: {
             x: 0,
             y: 0
@@ -139,7 +139,8 @@ Kinetic.Shape.prototype = {
         }
     },
     /**
-     * apply shadow helper method
+     * apply shadow based on shadowColor, shadowBlur,
+     * and shadowOffset properties
      */
     applyShadow: function() {
         var context = this.getContext();