Standard output policy

[rimms]

When parameter check error has occurred, jubatus prints messages for standard error.
like this: https://github.com/jubatus/jubatus/blob/master/src/framework/server_util.cpp#L155

But, other some command line tools(e.g. jubaconfig, jubactl, ...) print error messages for standard output.
like this: https://github.com/jubatus/jubatus/blob/master/src/cmd/jubaconfig.cpp#L106

I think, these should be unified to output for standard error.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

Closing this issue after a prolonged period of inactivity. Please feel free to create a new issue or re-open it if you need.