Add the stock holder data structure.
Create StockHolderTop10 class.
Crawl the top 10 stock holders.
Get top10 holder for all stocks and store them into database.
BUG FIX: The holding share should have larger data type: int -> bigint
Merge pull request #22 from wangjingfei/issue-19

Issue 19 - Crawl the top 10 stock holders.