Handle JSON requests with spaces and dots

As suggested in the [docs on php.net](http://us3.php.net/manual/en/function.parse-str.php#43317) `parse_str` will convert spaces and dots to underscores. The workaround already in place in bullet needs a little tweaking when you send a request like:

~~~json
{
    "link" : "http://www.google.com"
}
~~~

Because the current resulting `$params` from `parse_str` will look like something this:
~~~
Array
(
    [{"link":"http://www_google_com"}] => ""
)
~~~

The result is that we don't detect this situation and don't parse the body into the request object.