Post method should take arrays, not JSON strings.

[JonathanAquino]

The PostArticle example shows that you have to give it JSON strings for the article and the metadata.

However, this is a bit silly - the Post() method should take care of JSON-encoding the arrays that we give it.

Please allow Post() to accept arrays for the 'json' and 'metadata' parameters - it is a lot more natural for a PHP API than requiring JSON strings.