Option to omit top-level element wrapping

[GoogleCodeExporter]

What steps will reproduce the problem?
1. printToJson from a Message
2.
3.

What is the expected output? What do you see instead?
Expected for a message
Person {
 optioanl string name = 1;
}

with the value name = test:

{ "name": "test" }

Actual:

{ "person": { "name": "test" }}

What version of the product are you using? On what operating system?
2.3.0 on osx

Please provide any additional information below.

This top-level wrapping isn't very json-esque but more like what you would see 
in xml. It should be possible to disable.

Original issue reported on code.google.com by storsv...@telenordigital.com on 13 Jun 2012 at 9:02