Sync _.isFinite changes with Underscore and update vendor/underscore and vendor/backbone.

Former-commit-id: 9acb93a276a11da8186da76bd82f1fd6f89c27dd

vendor/backbone/test/model.js

@@ -55,6 +55,17 @@ $(document).ready(function() {
     equal(model.get('value'), 2);
   });
 
+  test("parse can return null", 1, function() {
+    var Model = Backbone.Model.extend({
+      parse: function(obj) {
+        obj.value += 1;
+        return null;
+      }
+    });
+    var model = new Model({value: 1}, {parse: true});
+    equal(JSON.stringify(model.toJSON()), "{}");
+  });
+
   test("url", 3, function() {
     doc.urlRoot = null;
     equal(doc.url(), '/collection/1-the-tempest');

vendor/backbone/test/router.js

@@ -481,4 +481,15 @@ $(document).ready(function() {
     });
   });
 
+  test("#1746 - Router allows empty route.", 1, function() {
+    var Router = Backbone.Router.extend({
+      routes: {'': 'empty'},
+      empty: function(){},
+      route: function(route){
+        strictEqual(route, '');
+      }
+    });
+    new Router;
+  });
+
 });

vendor/backbone/test/sync.js

@@ -17,6 +17,11 @@ $(document).ready(function() {
       Environment.prototype.setup.apply(this, arguments);
       library = new Library;
       library.create(attrs, {wait: false});
+    },
+
+    teardown: function() {
+      Environment.prototype.teardown.apply(this, arguments);
+      Backbone.emulateHTTP = false;
     }
 
   }));
@@ -157,4 +162,23 @@ $(document).ready(function() {
     this.ajaxSettings.error();
   });
 
+  test("#1756 - Call user provided beforeSend function.", 4, function() {
+    Backbone.emulateHTTP = true;
+    var model = new Backbone.Model;
+    model.url = '/test';
+    var xhr = {
+      setRequestHeader: function(header, value) {
+        strictEqual(header, 'X-HTTP-Method-Override');
+        strictEqual(value, 'DELETE');
+      }
+    };
+    model.sync('delete', model, {
+      beforeSend: function(_xhr) {
+        ok(_xhr === xhr);
+        return false;
+      }
+    });
+    strictEqual(this.ajaxSettings.beforeSend(xhr), false);
+  });
+
 });