Rewrote Deferred selection code to not use "window".

This means it can be used in a web worker.

src/backend.csv.js

@@ -8,7 +8,7 @@ this.recline.Backend.CSV = this.recline.Backend.CSV || {};
   my.__type__ = 'csv';
 
   // use either jQuery or Underscore Deferred depending on what is available
-  var Deferred = _.isUndefined(window.jQuery) ? _.Deferred : jQuery.Deferred;
+  var Deferred = (typeof jQuery !== "undefined" && jQuery.Deferred) || _.Deferred;
 
   // ## fetch
   //

src/backend.dataproxy.js

@@ -13,7 +13,7 @@ this.recline.Backend.DataProxy = this.recline.Backend.DataProxy || {};
 
   
   // use either jQuery or Underscore Deferred depending on what is available
-  var Deferred = _.isUndefined(window.jQuery) ? _.Deferred : jQuery.Deferred;
+  var Deferred = (typeof jQuery !== "undefined" && jQuery.Deferred) || _.Deferred;
 
   // ## load
   //

src/backend.elasticsearch.js

@@ -7,7 +7,7 @@ this.recline.Backend.ElasticSearch = this.recline.Backend.ElasticSearch || {};
   my.__type__ = 'elasticsearch';
 
   // use either jQuery or Underscore Deferred depending on what is available
-  var Deferred = _.isUndefined(window.jQuery) ? _.Deferred : jQuery.Deferred;
+  var Deferred = (typeof jQuery !== "undefined" && jQuery.Deferred) || _.Deferred;
 
   // ## ElasticSearch Wrapper
   //

src/backend.gdocs.js

@@ -7,7 +7,7 @@ this.recline.Backend.GDocs = this.recline.Backend.GDocs || {};
   my.__type__ = 'gdocs';
 
   // use either jQuery or Underscore Deferred depending on what is available
-  var Deferred = _.isUndefined(window.jQuery) ? _.Deferred : jQuery.Deferred;
+  var Deferred = (typeof jQuery !== "undefined" && jQuery.Deferred) || _.Deferred;
 
   // ## Google spreadsheet backend
   // 

src/backend.memory.js

@@ -7,7 +7,7 @@ this.recline.Backend.Memory = this.recline.Backend.Memory || {};
   my.__type__ = 'memory';
 
   // private data - use either jQuery or Underscore Deferred depending on what is available
-  var Deferred = _.isUndefined(window.jQuery) ? _.Deferred : jQuery.Deferred;
+  var Deferred = (typeof jQuery !== "undefined" && jQuery.Deferred) || _.Deferred;
 
   // ## Data Wrapper
   //

src/model.js

@@ -6,7 +6,7 @@ this.recline.Model = this.recline.Model || {};
   "use strict";
 
 // use either jQuery or Underscore Deferred depending on what is available
-var Deferred = _.isUndefined(window.jQuery) ? _.Deferred : jQuery.Deferred;
+var Deferred = (typeof jQuery !== "undefined" && jQuery.Deferred) || _.Deferred;
 
 // ## <a id="dataset">Dataset</a>
 my.Dataset = Backbone.Model.extend({