Added convenience functions getEndpointWithName and getEndpointsContainingName to Topology
Added convenience functions getRouterWithName, getRoutersContainingName, getLinkWithName, getLinksContainingName to Topology
Changed ClientServerTopology to be CloudTopology with n-number of senders and n-number of receivers; Incorporated the convenience methods in Topology for the getters in DirectTopology and CloudTopology; Added endpoint mappings for senders and receivers in Topology