Improve ChromeLogger data-rendering

[mindplay-dk]

Improve rendering of nested JSON data-structures in log.ts.

Currently, it's a simple JSON.stringify() - we'd like to add the ability to expand/collapse nested data-structures as in the regular console with the old extension.

Also, consider adding support for ___class_name as described in the original spec - it never worked properly; it only worked for the top-most object - if implemented, it should work for nested objects as well.