On create resource and link diagram, id should be a generated unique identifier (uuid)

[cgourdin]

Hello,

On OCCI specification document (GFD.185 - RESTful HTTP Rendering, section 3.1 - p6), the id representing a resource must be identified with a unique UUID.
For server usage and saving resource purpose, CloudDesigner should generate an uuid (v4?) on id to replace "r1", "r2", "rN".
The method is fairly simple like this :

public static String createUUID() {
        return UUID.randomUUID().toString();
}

The attribute "occi.core.id" must be set as given by the spec with urn.

[cgourdin]

resolved with commit 35e1d94 and commit a9005c9