membase-cli: when multiple cmds invoked in one command (rebalance + add), output of all responses

for example:

$ ./membase rebalance --cluster=127.0.0.1:9000 --server-add=127.0.0.1:9001

returns (if successful):
SUCCESS: server added..

should return output of both add server and rebalance, e.g.,
Server added: SUCCESSFUL
Cluster rebalanced: SUCCESSFUL