give alternative interface to headersIn/Out, Cookies and so on

[peter-leonov]

rykomats does this in a right manner in ngxv8.

If you need to get a header value very-very fast you may not want to construct Nginx.HeadersIn object, bing it to the request object, GC it and so on. You want just a value, not all this burden.

But, for those like me, who like dotted notation (like window.location.hash) all those classes must be preserved and share the same C code under the hood.