Refactoring of the memberhsip aggregation task.

mcproxy/include/proxy/proxy_instance.hpp

mcproxy/include/proxy/querier.hpp

mcproxy/include/proxy/routing_management.hpp

mcproxy/include/proxy/simple_membership_aggregation.hpp

mcproxy/include/proxy/simple_routing_management.hpp

mcproxy/mcproxy.pro

mcproxy/src/main.cpp

mcproxy/src/proxy/proxy_instance.cpp

mcproxy/src/proxy/querier.cpp

mcproxy/src/proxy/simple_membership_aggregation.cpp

mcproxy/src/proxy/simple_routing_management.cpp