Make entity.id a true guid and add property index

[GGAlanSmithee]

What is now entity.id, is in fact entity.index, so let's name it wat it is, and make id be a guid instead.

[GGAlanSmithee]

es6 compatible guid snippet:

function uuidv4() {
  return ([1e7]+-1e3+-4e3+-8e3+-1e11).replace(/[018]/g, c =>
    (c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16)
  )
}

console.log(uuidv4());

source / credit