Update tiny-json.c

[smdjeff]

fix for json_getProperty not finding the object if it's the first element.

[Alcantor]

By reading the comments, I do understand that the json_getPropertyValue() function search a property into an object and returning the object itself sould not be possible, otherwise we no more searching into it.

What about: { "propA": { "propA": "testValue"}}

If I want to get the property "propA" of "propA", do I get "testValue" after this patch. I do not have tested it, but I'am a little bit concerned.