Fix default encoding for outgoing HTTP messages

Was causing send() to throw argument errors because arrays of ints would get
paired with the "raws" encoding. The bug was introduced in 8eb1294.

src/http.js

@@ -173,7 +173,8 @@ node.inherits(OutgoingMessage, node.EventEmitter);
 
 OutgoingMessage.prototype.send = function (data, encoding) {
   this.output.push(data);
-  this.outputEncodings.push(encoding || "raws");
+  encoding = encoding || (data.constructor === Array ? "raw" : "raws");
+  this.outputEncodings.push(encoding);
 };
 
 OutgoingMessage.prototype.sendHeaderLines = function (first_line, headers) {