(reposted from ipfs/specs#112)

Originally in interplanetary paths I included the possibility of having relative paths.

Here I am proposing to add in the specs (and in the js-ipld implementation), the ability to resolve relative paths.
Having relative paths saves space (../, instead of a full hash), helps avoiding splitting things in multiple pieces (../ instead of creating a new object) and finally, allow circular relationships: merkle graph!

{
  nicola: { '/': hashNicola },
  david: { '/': hashDavid }
}

{
  name: "Nicola",
  friends: [{'/':'../david' }]
}

{
  name: "David",
  friends: [{'/':'../nicola' }]
}

cc @jbenet, @mildred, @dignifiedquire