Add setLocale

[fiote]

I post in multiple idioms on my page so I need to be able to select the language when requesting the feed. I updated my version of your package locally but it would be nice if you could add it to the base code. Here are the changes :)

line 17
private $locale = null;

line 80

    /**
     * @param $locale
     * @return $this
     */
    function setLocale($locale) {
        $this->locale = $locale;
        return $this;
    }

line 142

            if ($this->locale) {
                $query['query']['locale'] = $this->locale;
            }

[xmhafiz]

great, please create a pull request

[afiqiqmal]

#10 Pull Request