rename bottom2 class to footer
the position of splitter should not change when drag/enddrag
minor fix
Merge branch '7.0' of https://github.com/zkoss/zk into fix-ie8
Merge branch '7.0' of https://github.com/zkoss/zk into fix-ie8
minor fix
Merge branch '7.0' of https://github.com/zkoss/zk into fix-ie8
grid, listbox, tree for IE8