[hatohol-config-db-creator] Add a function to create users.
[FaceRest] Log an error for a request as INFO.

The reason of the error is mainly due to parameters given by the
client. So it's not an error of Hatohol itself.
[hatohol-def-src-generator] Use the generation function that can be commonly used between JS and Python.
[hatohol-def-src-generator] Add constant definitions of HatoholError.
[hatohol-def-src-generator] Add constant definitions of DataQueryOption.
[hatohol-def-src-generator] Clean up.
[hatohol-def-src-generator] Clean up.
[voyager] Add an option to specifiy the sort order of events.
[voyager][test] Add tests for sort order.
[voyager] Add an option to limit the number of returned events.
[voyager] Add a short version of --max-number.
[voyager] Add comments to be easy to see tests for a feature.
[voyager] Add an option to specify the start ID.
[FaceRest] Propagate an error of DBClientHatohol to the client.