Encodes list of lists of integers into a Buffer according to
https://github.com/statebox/nll-spec
Import library
const nll = require('nll')
//=> { encode: [[number]] -> Buffer,
// decode: Buffer -> [[number]] }Encode
> b = nll.encode([[-1],[0],[],[1]])
//=> <Buffer 0f 00 01 00 02 00 00 04>Decode
> n.decode(b)
[ [ -1 ], [ 0 ], [], [ 1 ] ]