compiled on Ubuntu 14.04.2 LTS, x86_64

improvements:

1. add proc. you can collect query's internal status via task
2. use simple rcp connection pool
3. add last_raw interface. you can fetch raw values of COUNTER type

// change logs // 1.3.2 add last api for querying last item // 1.3.3 rm debug log in http.graph // 1.3.4 add http-api /graph/last/raw // 1.3.5 fill response with endpoint & counter when rpc Graph.Query getting errors // 1.4.0 restruct query: use simple rpc conn pool // 1.4.1 add last item counter, add proc for connpool // 1.4.2 rm nil items in http.responses