Engine based Json encoding

[David Bovill]

I'm taking a look at the new json handline in Livecode - as it's core to
what we're working on. I'm getting my head around the new version of Create
and Classic - so does anyone know any nuances regarding how to tell if it's
using the native engine version - and any gotcha's regarding encoding -
I've so many different versions of json handling from the past to ensure
compatibility:

   - https://future.livecode.com/dp2-json/