docs: function relativize (dest, src) {
    // both of these are absolute paths.
    // find the shortest relative distance.
    src = src.split("/")
    var abs = dest
    dest = dest.split("/")
    var i = 0
    while (src[i] === dest[i]) i++
    if (i === 1) return abs // nothing in common, leave absolute
    src.splice(0, i + 1)
    var dots = [0, i, "."]
    for (var i = 0, l = src.length; i < l; i ++) dots.push("..")
    dest.splice.apply(dest, dots)
    dest = dest.join("/")
    return abs.length < dest.length ? abs : dest
  }