Some minor fixes and changes

Squashed commits:
Fix opacity on SkeletonAnimation not working issue
[89cd5f4] More exigent check for sprite need draw
[48f6fda] Use standard blend function for layer
[9065802] Made webgl background not transparent
[f5d3416] Fix variable leak in ProgressTimerRenderCmd

Author: pandamicro

Diff for: CCBoot.js

@@ -2654,7 +2654,7 @@ cc.game = /** @lends cc.game# */{
                 'stencil': true,
                 'preserveDrawingBuffer': true,
                 'antialias': !cc.sys.isMobile,
-                'alpha': true
+                'alpha': false
             });
         }
         // WebGL context created successfully

Diff for: cocos2d/core/layers/CCLayer.js

@@ -191,7 +191,7 @@ cc.LayerColor = cc.Layer.extend(/** @lends cc.LayerColor# */{
      */
     ctor: function(color, width, height){
         cc.Layer.prototype.ctor.call(this);
-        this._blendFunc = new cc.BlendFunc(cc.SRC_ALPHA, cc.ONE_MINUS_SRC_ALPHA);
+        this._blendFunc = cc.BlendFunc._alphaNonPremultiplied();
         cc.LayerColor.prototype.init.call(this, color, width, height);
     },
 

Diff for: cocos2d/core/sprites/CCSpriteWebGLRenderCmd.js

@@ -531,7 +531,7 @@
     };
 
     proto.needDraw = function () {
-        return (this._buffer && this._node._texture);
+        return (this._buffer && this._needDraw);
     };
 
     proto.rendering = function (ctx) {

Diff for: cocos2d/progress-timer/CCProgressTimerWebGLRenderCmd.js

@@ -197,7 +197,7 @@
             this._vertexArrayBuffer = new ArrayBuffer(MAX_VERTEX_COUNT * vertexDataLen);
             this._float32View = new Float32Array(this._vertexArrayBuffer);
             this._vertexData = [];
-            for (i = 0; i < MAX_VERTEX_COUNT; i++) {
+            for (var i = 0; i < MAX_VERTEX_COUNT; i++) {
                 this._vertexData[i] = new cc.V3F_C4B_T2F(null, null, null, this._vertexArrayBuffer, i * vertexDataLen);
             }
 

Diff for: extensions/spine/CCSkeletonCanvasRenderCmd.js

@@ -197,7 +197,7 @@
                 }
 
                 //hack for sprite
-                selSprite._renderCmd._displayedOpacity = 0 | (locSkeleton.a * slot.a * 255);
+                selSprite._renderCmd._displayedOpacity = 0 | (this._node.getOpacity() * locSkeleton.a * slot.a);
                 var r = 0 | (locSkeleton.r * slot.r * 255), g = 0 | (locSkeleton.g * slot.g * 255), b = 0 | (locSkeleton.b * slot.b * 255);
                 selSprite.setColor(cc.color(r,g,b));
                 selSprite._renderCmd._updateColor();