update docs to include the new zepto data module requirement
update docs to include the new zepto data module requirement

akre54/backbone.stickit,akre54/backbone.stickit,GerHobbelt/backbone.stickit,NYTimes/backbone.stickit,adam-26/backbone.stickit,Krasnyanskiy/backbone.stickit,NYTimes/backbone.stickit,adam-26/backbone.stickit,Krasnyanskiy/backbone.stickit