Added rudimentary json_info command

Hi kostya,

This is a simple, probably bad json_info command added to the `eye` CLI. I wanted to be able to feed `eye` status to other monitoring systems, and JSON is a great cross-language machine-readable format. 

json_info currently simply outputs the response from the eye server as ran through JSON.generate. I'm sure it can be prettified, but I have just started playing with it and wanted to get the ball rolling quickly. As I continue to work on this I may add refined output and specs for this.

What do you think? Do you want to change the command name?

Thanks,

Milan Iliev