Add option to pretty-print JSON and XML data

[RovoMe]

When receiving API responses that are not pretty-printed by default, it is sometimes hard to actually read the response. While copy/pasting the payload i.e. to Atom, specify the representation format and then apply pretty-printing to it solves the task, this actually involves multiple steps performed by the user and slows down the actual process.

While RESTED 2.5.0, which is installed in my Firefox browser, provide the options of wrapping responses that overflow the text-box, I don't see any option to actually pretty-print the response automatically or at least via an additional checkbox near the text-area where you can enable/disable pretty-printing.