add generic functions for (u)int ops - copied from node commit 83d7d9e
add generic functions for (u)int ops - copied from node commit 83d7d9e

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