Consider an option to pretty-print JSON

I often want to look at JSON things, and it would be easier if it were formatted nicely.

Mostly, I'm thinking about the json field of custom_json operations, but it would also be nice to have for account's JSON Metadata and Posting JSON Metadata, and there are probably a few other places where JSON is on the blockchain. For those, I'm happy to have the raw, unformatted version be the default, since it's showing me what's really on the blockchain. But it would be nice to have a pretty-print button that I could hit when I want to actually read it, something like the pretty-print toggle button ({}) in firefox/chrome developer tools's source view. Right now I have to copy it and paste it into an external JSON pretty-printer.

I'd kind of like the option when looking at Raw Json view for blocks and transactions too. A similar toggle would be fine here, but I'd also be good with making pretty-printed the default, or making it a global option that I could leave checked. The JSON view here is just showing me a representation of the binary data on the blockchain, so both minified and pretty-printed would seem equally valid. I don't think I've ever wanted to see the minified version.

Issue #201 (closed) seems to be where you started printing JSON in minified form, but I'm not sure what it looked like before that was changed.