anchor.diff:              "message" : "the specified key is not found"
               "data" : "optional error data" 
           }  
  +
  +## Game VFS  [/v1/vfs/{domain}/{key}]
  +
  +Game VFS is a key-value store you can use to associate data with a game. 
  +
  +Use it to store level, booard... any data your game would like to share among users.
  + 
  +### Get game's data [GET]
  +
  +###### Possible values for error 404
  +* `Key not found` ... the specified key doesn't exist
  +* `Domain not found` ... the specified domain doesn't exist
  +
  ++ Parameters
  +    + domain (required, string, `private`) ... the domain where to retreive the key/value
  +    + key (optional, string) ... the desired key, if omited all keys and values of the domains will be returned
  +
  ++ Request (application/json)
  +
  +    + Headers
  +    
  +            x-apikey : testgame-key
  +            x-apisecret : testgame-secret
  +            
  ++ Response 200 (application/json)
  +
  +        {
  +            "key" : "data which could be a json"
  +        }
  +
  ++ Request (application/json)
  +
  +    + Headers
  +    
  +            x-apikey : testgame-key
  +            x-apisecret : testgame-secret
  +            
  ++ Response 200 (application/json)
  +
  +        {
  +            "key1" : "any json value, object, array for key1",
  +            "key2" : "any json value, object, array for key2",
  +            "key3" : "any json value, object, array for key3",
  +            "key4" : "any json value, object, array for key4"
  +        }
  +
  +
  ++ Response 404 (application/json)
  +
  +        {
  +            "code" : "Key not found",
  +            "message" : "the specified key is not found"
  +            "data" : "optional error data" 
  +        }  
  +
  +### Set game's data [PUT]
  +
  +You can store data easily. Simply send the data to be stored, as a JSON object, in the body of the request. Note that simple strings are not allowed. Arrays and objects are.
  +
  +**if key don't exist, they are created**
  +
  ++ Parameters
  +    + domain (required, string, `private`) ... the domain where to store the key/value
  +    + key (required, string) ... the desired key
  +
  ++ Request (application/json)
  +
  +    + Headers
  +    
  +            x-apikey : testgame-key
  +            x-apisecret : testgame-secret
  +            
  +    + Body
  +    
  +            {"whatever": "your JSON value"}
  +            
  ++ Response 200 (application/json)
  +
  +    + Body
  +    
  +            1
  + 
  +    
  +### Remove game's data [DELETE]
  +
  +    NOTE : we can't yet distinguish a missing key from an incorrect domain...
  +
  +###### Possible reasons for error 404
  +* `Key not found` ... the specified key doesn't exist
  +* `Domain not found` ... the specified domain doesn't exist
  +
  ++ Parameters
  +    + domain (required, string, `private`) ... the domain from where to get the key/value
  +    + key (optional, string) ... the key to be removed (all if not specified)
  +
  ++ Request
  +
  +    + Headers
  +    
  +            x-apikey : testgame-key
  +            x-apisecret : testgame-secret
  +            
  ++ Response 200 (application/json)
  +
  +    + Body
  +    
  +            1
  +        
  ++ Response 404 (application/json)
  +
  +        {
  +            "code" : "Key not found",
  +            "message" : "the specified key is not found"
  +            "data" : "optional error data" 
  +        }  
  +
   
   # Group transactions
   
  
positive.code: 
  # Group Social features
  
  ## GET /v1/gamer/friends/{?status}
  
  + Parameters
      + status (optional, string) ... "blacklist" to retrieve the blacklisted gamer's
  
negative.code:             {"<gamer_id_2>" : { displayName : "gamer2", lang : "fr" } }
          ] }
          
  ### POST /v1/gamer/friends/{friendid}?{status}
  
  + Parameters
      + friendid (required, string) ... a gamer id
  