function fetchFile(filePath) {
    return $http.post('fetch/dropbox', {mdFile: filePath}).then(
      function successCallback(response){
        dropboxService.fetched.file = response.data.data;
        return dropboxService.fetched.file;
      }, function errorCallback(err){
        return diNotify({
          message: 'An Error occured: ' + err
        });
      });
  }
Fetch File from Dropbox.

   @param  {String}  filePath  Path to the file on Dropbox.