bindJson: support for nested `with`'s

[srid]

It seems I cannot use nested JSON in heist templates. In the inner Json handling location, I can't access the outer Json's field.

Is this by design, or is simply a limitation of explodeTag's current implementation?

[srid]

Example:

• Binding outter JSON's settings.theme field: https://github.com/srid/emabook/blob/4e2d091b7e9e1687818f37d865a3cb90044a5135/docs/.emabook/templates/_default.tpl#L25
• Define another JSON, and drop into it using <with ...>. The <theme/> tag will now be out of scope inside the with tag.