[docs] Unclear part for client.retrieve()

[wanghongjuan]

Description

According to description for retrieve method, there is written that Returns a promise which resolves to a ClientResource containing the resource properties, but the spec doesn't defined what is ClientResource. In https://github.com/01org/zephyr.js/blob/master/docs/ocf.md#ocf-client, the retrieve method return a Resource object, this description doesn't align with above content, if the method returns a resource object that only contain two members resourcePath and properties, but in this sample, it has other member deviceId. And I'm not clear what is the difference about the Resource interface between server and client.

BTW, method Client.findResources also has same problem with retrieve().

[wanghongjuan]

Object OCFResource in register() method has same behavior with the ClientResource object, the spec doesn't defined what are properties for it .