opti: 优化svg tags：兼容小写，删掉了废弃的animateColor，添加了linearGradient,radialGrad…

…ient,stop等渐变相关标签，fix #621

src/browser/create-el.js

@@ -17,7 +17,7 @@ var svgTags = require('./svg-tags');
  */
 function createEl(tagName) {
     if (svgTags[tagName] && document.createElementNS) {
-        return document.createElementNS('http://www.w3.org/2000/svg', tagName);
+        return document.createElementNS('http://www.w3.org/2000/svg', svgTags[tagName]);
     }
 
     return document.createElement(tagName);

src/browser/svg-tags.js

@@ -16,18 +16,39 @@ var splitStr2Obj = require('../util/split-str-2-obj');
  * @type {Object}
  */
 var svgTags = splitStr2Obj(''
-    // structure
-    + 'svg,g,defs,desc,metadata,symbol,use,'
-    // image & shape
-    + 'image,path,rect,circle,line,ellipse,polyline,polygon,'
-    // text
-    + 'text,tspan,tref,textpath,'
-    // other
-    + 'marker,pattern,clippath,mask,filter,cursor,view,animate,'
-    // font
-    + 'font,font-face,glyph,missing-glyph,'
-    // camel
-    + 'animateColor,animateMotion,animateTransform,textPath,foreignObject'
+    // Animation elements
+    + 'animate,animateMotion,animateTransform,'
+
+    // Basic shapes
+    + 'circle,ellipse,line,polygon,polyline,rect,'
+
+    // Container elements
+    + 'defs,g,marker,mask,missing-glyph,pattern,svg,symbol,'
+
+    // Descriptive elements
+    + 'desc,metadata,'
+
+    // Font elements
+    + 'font,font-face,'
+
+    // Gradient elements
+    + 'linearGradient,radialGradient,stop,'
+
+    // Graphics elements
+    + 'image,path,use,'
+
+    // Text elements
+    + 'glyph,textPath,text,tref,tspan,'
+
+    // Others
+    + 'clipPath,cursor,filter,foreignObject,view'
 );
 
+// 把小写转驼峰：HTML中的svg标签不区分大小写，但通过document.createElementNS创建需要区分
+for (var tag in svgTags) {
+    if (/[A-Z]/.test(tag)) {
+        svgTags[tag.toLowerCase()] = svgTags[tag];
+    }
+}
+
 exports = module.exports = svgTags;