fixed nullalgo::query_cht() always return large datum

+ added nullalgo::query_cht_nolock(). query_cht_nolock is
  same as query_cht except use @nolock
+ added rpc_bench --method METHOD. METHOD is one of
  query_cht(default), query_cht_large, query_cht_nolock
+ added rpc_bench --dump-latency. it dumps all latency
  records in one line
modified: share nullalgo_serv.*, idl and rpc-benc between 0.3 and 0.4