Correct problem with over-escaped NUL for PLAIN auth

The plain AUTH was separating the username and password with
"\\0". These are two characters, 5C '\' 30 '0' .

This patch changes it to use "\0" which is a single character, 00 NUL.

It also includes a test script to try sending email with only PLAIN
auth.

smtp/smtp.js

@@ -457,7 +457,7 @@ SMTP.prototype =
    
          encode_plain = function()
          {
-            return (new Buffer("\\0" + login.user() + "\\0" + login.password())).toString("base64");
+            return (new Buffer("\0" + login.user() + "\0" + login.password())).toString("base64");
          };
    
          // List of authentication methods we support: from preferred to

test/authplain.js

@@ -0,0 +1,87 @@
+describe("authorize plain", function()
+{
+   var simplesmtp = require("simplesmtp");
+   var expect     = require("chai").expect;
+   var fs         = require("fs");
+   var os         = require("os");
+   var path       = require('path');
+   var email      = require('../email');
+   var port       = 2526;
+   var server     = null;
+   var smtp       = null;
+
+   var send = function(message, verify)
+   {
+      smtp.on("startData", function(envelope)
+      {
+         envelope.parser = new (require("mailparser").MailParser)({defaultCharset:"utf-8"});
+         envelope.parser.on("end", function(mail)
+         {
+            verify(mail);
+            smtp.removeListener("startData", arguments.callee);
+         });
+      });
+
+      server.send(message, function(err) 
+      {
+         if(err)
+            throw err;
+      });
+   }
+
+   before(function(done)
+   {
+      smtp = simplesmtp.createServer({secureConnection:true,
+                                      requireAuthentication:true,
+                                      authMethods: ["PLAIN"]});
+
+      smtp.listen(port, function()
+      {
+         smtp.on("data", function(envelope, chunk)
+         {
+            envelope.parser.write(chunk);
+         });
+         
+         smtp.on("dataReady", function(envelope, callback)
+         {
+            envelope.parser.end();
+            callback(null);
+         });
+
+         done();
+      });
+   });
+
+   after(function(done)
+   {
+      smtp.end(done);
+   });
+
+   it("login", function(done)
+   {
+      server = email.server.connect({port:port, user:"piglet", password:"haycorns", ssl:true});
+
+      var message =
+      {
+         subject: "this is a test TEXT message from emailjs",
+         from:    "piglet@gmail.com",
+         to:      "pooh@gmail.com",
+         text:    "It is hard to be brave when you're only a Very Small Animal."
+      };
+
+      smtp.on("authorizeUser", function(envelope, username, password, callback)
+      {
+         smtp.removeListener("authorizeUser", arguments.callee);
+         callback(null, username == "piglet" && password == "haycorns")
+      });
+
+      send(email.message.create(message), function(mail)
+      {
+         expect(mail.text).to.equal(message.text + "\n\n");
+         expect(mail.headers.subject).to.equal(message.subject);
+         expect(mail.headers.from).to.equal(message.from);
+         expect(mail.headers.to).to.equal(message.to);
+         done();
+      });
+   });
+});