added auto_blogger function in DescCharacterLimit

Added auto_blogger option in DescCharacterLimit, this option search for Blogger.com Read More and calculates the character limit.
Search by `<a name="more"></a>` (blogger jump break), famous Read More and show substring (0, jumpBreakPosition).

**How to Use:**
$('#divRss').FeedEk({
   FeedUrl : 'http://blog.arthurassuncao.com/atom.xml', /*blogger atom link*/
   MaxCount : 3,
   ShowDesc : true,
   ShowPubDate: true,
   DescCharacterLimit: **'auto_blogger'**,
   TitleLinkTarget: '_blank'
});

See in action: http://arthurassuncao.com