only do console.log() mode, fix double \n bug

lib/default_stream.js

@@ -1,23 +1,28 @@
 var Stream = require('stream');
 
 module.exports = function () {
-    if (typeof process !== 'undefined' && process.stdout
-    && typeof process.stdout.pipe === 'function') {
-        return process.stdout;
-    }
-
     var out = new Stream;
     out.writable = true;
+    var buffered = '';
 
     out.write = function (buf) {
-        console.log(String(buf));
+        var s = buffered + String(buf);
+        var lines = s.split('\n');
+        for (var i = 0; i < lines.length - 1; i++) {
+            console.log(lines[i]);
+        }
+        buffered = lines[i];
     };
 
     out.destroy = function () {
+        out.writable = false;
         out.emit('close');
     };
 
-    out.end = function () {
+    out.end = function (msg) {
+        if (msg !== undefined) out.write(msg);
+        if (buffered) console.log(buffered);
+        out.writable = false;
         out.emit('close');
     };