replace 'img' class name with 'image'
* adjust caption dom, rm !important in groupbox.less
* adjust label and button style in caption.less
Merge branch '7.0' of https://github.com/zkoss/zk into update-groupbox
rename 'input' class to 'content' class
borderlayout use custom scrollbar
Merge branch 'update-groupbox' of git://github.com/huangnoah/zk into 7.0
Merge branch 'update-combobutton' of git://github.com/huangnoah/zk into 7.0