swarm/storage/mru: Renamed all identifiers to Feeds

cmd/swarm/mru.go

cmd/swarm/mru_test.go

swarm/api/api.go

swarm/api/client/client_test.go

swarm/api/http/server.go

swarm/api/http/server_test.go

swarm/api/manifest.go

swarm/network/README.md

swarm/storage/mru/cacheentry.go

swarm/storage/mru/doc.go

swarm/storage/mru/handler.go

swarm/storage/mru/handler_test.go

swarm/storage/mru/id.go

swarm/storage/mru/id_test.go

swarm/storage/mru/query.go

swarm/storage/mru/query_test.go

swarm/storage/mru/request.go

swarm/storage/mru/request_test.go

swarm/storage/mru/testutil.go

swarm/storage/mru/topic.go