Add documentation on language specific implementation libraries

[embray]

It can't hurt to add a chapter listing and describing how to actually use some JSON Schema implementations. While I don't think it should serve as a full replacement for those projects' own documentation it can't hurt to point to the best libraries available for a given language and some basic examples of how to use them.

I'll assign myself this since it's my idea.

[mdboom]

Sure. You probably already know this, but there's already a reasonable list here: http://json-schema.org/implementations.html It, of course, doesn't give examples. My concern about this proposal is keeping it up to date. We should, at a minimum, let the authors of those tools know about this so they can flag things when the API changes etc.

[embray]

I think I had seen that page before I had forgotten about it when I wrote this. Agree that the moving target issue is problematic. I mostly had in mind to just give a flavor of what it "looks like" to validate a JSON Schema in software.