LocalDataFetcher = function($http) {
  /** @private {!angular.$http} */
  this.http_ = $http;

  /** @private {string} */
  this.template_ = '../../data/{q}.json';
}
Fetches stock data by querying local disk (no network connection required).
The data must have been fetched before-hand with the prefetch_data.js nodejs
script.
@constructor

@param {!angular.$http} $http