Ticket  47600 : Replica/Agreement/Changelog not conform to the design
    
    Bug Description:
    	Currently all replication functions are in brooker/__ini__.
    	To conform the design, we need to split these functions into various classes
    	Replica/Agreement/Changelog (and files) and to remove them from brooker/__init__.
    	Also to change the interfaces (list/create/delete/set/get..).
    
    Fix Description:
    	Create Agreement/Replica/Changelog classes with (list/create/delete/set-getProperties...)
    	Add unit tests for Replica and RA
    	Fix some issues found with unit tests
    
    https://fedorahosted.org/389/ticket/47600
    
    Reviewed by: Rich Megginson (thanks Rich !!)
    
    Platforms tested: F17
    
    Flag Day: no
    
    Doc impact: no