This adds JSON as an additional scripting documentation output format.
This can be used by external tools to examine the scripting
documentation and generate interface declarations or documentation for
any language. The existing documentation code is left largely in place.
This will automatically call the destructor of a type of Lua calls the
garbage collector for an object of that type. This is the last step
towards fully supporting non-trivial objects in the Lua API and all
previous workarounds have been removed.