spec:coveralls: define timeout for result merging
spec: generate local html simplecov report
spec: remove dead code
spec: cover explorer
support node migration
pass heartbeat parameters as DCell options
spec: use relaxed heartbeat parameters
spec: gently merge coverage of killed node
registries: remove registry notification on node relocation(for now)
spec/travis: add cassandra(a trial)
travis: add zk job
rake: remove zk and cassandra install tasks, should be configured on test box via normal distro workflow