XWIKI-8935: Upgrade to GWT 2.5.1
XWIKI-8935: Upgrade to GWT 2.5.1

xwiki/xwiki-platform,pbondoer/xwiki-platform,xwiki/xwiki-platform,pbondoer/xwiki-platform,pbondoer/xwiki-platform,xwiki/xwiki-platform,pbondoer/xwiki-platform,xwiki/xwiki-platform,xwiki/xwiki-platform,pbondoer/xwiki-platform