JSON5 support for std.json

[Chris Wright via Digitalmars-d]

I'm considering adding JSON5 support to std.json and want to know how 
well this would be received.

JSON5 is pretty much just modern JavaScript's object literal format, 
allowing things like comments, trailing commas, and single-quoted strings.

I only plan to add support for parsing JSON5, not emitting it. So there 
should be no compatibility concerns with what std.json emits.

Since it's technically a breaking change (people can use std.json 
currently to validate that a document is valid JSON), I am inclined to 
make JSON5 be off by default and add an option to parse JSON5 rather than 
JSON1. Anyone have strong feelings about this?