Add Hatena Bookmark Sharer.

Add Hatena Bookmark Sharer. 'Hatena Bookmark' is the most popular social bookmark service in japanese like delicious. The official URL is http://b.hatena.ne.jp/ . 

To use this sharer, get OAuth keys from developer site, http://developer.hatena.ne.jp/en , and fill these keys to SHKHatenaConsumerKey and SHKHatenaSecretKey macro.