"""
                 merging the defaulacl and the pageacl
                 ruleset(only one rule for a group or a user in the acl) : e.g. : UserOrGroup:write,read
                 acl : e.g. : User1:write,read Group2:write,read,admin
                 a) When a ruleset is only setted in the pageacl,
                    nothing is changed for this user/group
                 b) When a ruleset is only setted in the defaultacl,
                    the whole ruleset is appended to the pageacl
                 c) When a ruleset is setted in the pageacl with +rulset or -rulset and also given in the defaultacl,
                    the rulset of the defaultacl is appended to the end of the pageacl 
                 d) When a ruleset is setted in the pageacl with not +/-rulset and also given in the defaultacl
                    the rulset of the pageacl and the defaultacl is merged to one rulset 
                    and replacing the old ruleset in the pageacl
                 c) When a ruleset is setted in the pageacl with +/-rulset and not +/-rulset and is also given in the defaultacl
                    the ruleset which is not a +/-rulset is merged like d)
        """