CreateDocument does not generate an id

[Tyki]

When using createDocument method, the id is not automatically generated. Instead a string ':_id' is used as ID of document

Expected Behavior

A UUIDV4 as documentID

Current Behavior

string '_id' as documentID

Possible Solution

Steps to Reproduce

1. Setup SDK PHP
2. Get a collection object
3. Try to create a document without providing the second parameter 'id'

Context (Environment)

Kuzzle 1.5
SDK PHP 3.0.4