CHANGES.md: Note IE8 workaround change in ColumnHider
CHANGES.md: Note IE8 workaround change in ColumnHider

kfranqueiro/dgrid,dylans/dgrid,dylans/dgrid,dylans/dgrid,kfranqueiro/dgrid,maier49/dgrid,kfranqueiro/dgrid,maier49/dgrid,maier49/dgrid