By James Pomfret and Yimou Lee of Reuters ddddd SHENZHEN/HONGKONG — A planned economic zone in southern China will allow full internet freedom, similar to what will be allowed in a proposed free trade zone in Shanghai, a senior official behind the project said on Thursday.   fffff China tightly controls the internet through a so-called Great Firewall, routinely deleting online postings and blocking access to websites it deems politically sensitive or inappropriate such as Facebook...