// Makes sequential getJSON requests, passing the processed results from the
// previous request to the next request. seedData is optional.
var chainedGetJSON = function(requests, seedData) {
  var seed = $.Deferred(),
      finalPromise;

  finalPromise = requests.reduce(function(promise, request) {
    return promise.pipe(function(input) {
      return $.getJSON(request.url(input)).pipe(function(json) {
        return request.process(json, input);
      });
    });
  }, seed.promise());

  // Start the chain
  seed.resolve(seedData);

  return finalPromise;
};