Add optional color support

[JeffBelgum]

Json syntax highlighting would be a great addition to the library. One possibility is highlighting by default when stdout is a tty and no highlighting when stdout is a pipe or file. A --color flag could be used to override default behavior

[flo-l]

good suggestion, I will think about it! I'd also be happy to accept a PR :smile:

[BrainMaestro]

I'd like to work on this if @JeffBelgum doesn't pick it up

[flo-l]

@BrainMaestro sounds good! I suggest you add a color: bool member to PrettyFormatter and handle colors conditionally there. Feel free to open issues if you have any questions!

[JeffBelgum]

@BrainMaestro yeah go for it!

[rivertam]

For people like me who want this but don't care nearly enough to try to implement it, I recommend piping into bat. ./my-program | jsonpp | bat --language=json