fixed RPC return types and values
update graph.idl and regenerate source
fixed RPC return (stat#push)
fix: issue #152 -b, -B option added

-b, -B option added. -b/--listen_addr option specify bind
address of juba servers and keepers. This address is used
as a part of node-name for ZK. -B/--listen_if option specify
address by network interface name. When both -b and -B are
given, -B is ignored.
server_helper::start() will catch exceptions

server_helper::start() will catches exceptions raised by
rpc_server::serv() and report them by LOG(FATAL).
Merge pull request #209 from rimms/rpc-return

fixed RPC return types and values (2)
fix segfault when exception is thrown when initializing plugin : fixes #211
eliminate use of USER environment variable (fix #204)
Fix classifier.idl type in comment
add msgpack dependency to mprpc.h to avoid link error when using '-O0'
test if the directory exists (fix #206)
fix log output (fix #207)