NEW YORK (Reuters) - Eleven years after the September 11, 2001, attacks, New Yorkers will mark the anniversary on Tuesday against a backdrop of health concerns for emergency workers and a feud over financing that has stopped construction of the $1 billion Ground Zero museum. While notable progress on redevelopment of the World Trade Center has been made since early disputes over financial, design and security issues, the project remains hobbled by political battles and billions of dollars in cost overruns. ...