support svg background gradient for IE9
Merge branch '7.0' of github.com:zkoss/zk into 7.0
rm > selector
* replace cls + '-xxx' with this.$s('xxx')
* fix this.$s('content') by this.$s('cnt')
* [less] rm > selector, add lite mold style.
* [less] adjust accordion style and order to prevent nest style problem
Merge branch 'update-tabbox' of git://github.com/huangnoah/zk into 7.0