Added Symfony 2.8 to Travis tests
Added Symfony 2.8 to Travis tests

ogizanagi/EasyAdminBundle,datagit/EasyAdminBundle,alexgt9/EasyAdminBundle,kamilZ/EasyAdminBundle,yceruto/EasyAdminBundle,seydu/EasyAdminBundle,yceruto/EasyAdminBundle,datagit/EasyAdminBundle,alexgt9/EasyAdminBundle,javiereguiluz/EasyAdminBundle,seydu/EasyAdminBundle,thomasbeaujean/EasyAdminBundle,thomasbeaujean/EasyAdminBundle,ogizanagi/EasyAdminBundle,kamilZ/EasyAdminBundle,yceruto/EasyAdminBundle,ogizanagi/EasyAdminBundle,seydu/EasyAdminBundle,datagit/EasyAdminBundle,thomasbeaujean/EasyAdminBundle,gabiudrescu/EasyAdminBundle,OskarStark/EasyAdminBundle,alexgt9/EasyAdminBundle,ogizanagi/EasyAdminBundle,kamilZ/EasyAdminBundle,gabiudrescu/EasyAdminBundle,gabiudrescu/EasyAdminBundle,OskarStark/EasyAdminBundle,javiereguiluz/EasyAdminBundle,OskarStark/EasyAdminBundle