-(AlfrescoRequest *)
                retrieveAllSitesWithCompletionBlock:(AlfrescoArrayCompletionBlock)completionBlock
            - retrieves a list of sites in the repository that the current user has visibility
            of.
        Parameters
- (NSString *) siteShortName
 - The name of the site.
 - (AlfrescoArrayCompletionBlock) completionBlock
 - The block that is called with the sites on completion of the operation. The completion block has the format typedef void (^AlfrescoArrayCompletionBlock)(NSArray *array, NSError *error).
 
Returns
(AlfrescoRequest *)
Example