use object literal syntax rather than explicitly calling the constructor

content/addressbook.js

@@ -192,7 +192,7 @@ liberator.Addressbook = function () //{{{
 			if (newMail)
 			{
 				// Now we have to create a new message
-				var args = new Object();
+				var args = {};
 				args.to = addresses.map(function (address)
 				{
 					return "\"" + address[0].replace(/"/g, "") + " <" + address[1] + ">\"";

content/mail.js

@@ -678,7 +678,7 @@ liberator.Mail = function () //{{{
         "Write a new message",
         function (args, special, count)
         {
-            var mailargs = new Object();
+            var mailargs = {};
             mailargs.to =          args.arguments.join(", ");
             mailargs.subject =     args["-subject"];
             mailargs.bcc =         args["-bcc"];