drop opera 11 support
drop opera 11 support

beni55/buffer,btd/buffer,LiuDeng/buffer,loon3/buffer,feross/buffer,feross/buffer,SAGV/buffer,nolanlawson/buffer,nolanlawson/buffer,LiuDeng/buffer,beni55/buffer,LinusU/buffer,jessetane/buffer,kawanet/buffer,kawanet/buffer,feross/buffer,SAGV/buffer,loon3/buffer,btd/buffer,LinusU/buffer