Firefox will try to parse the response from POST requests, causing a …

…syntax error message in the Web Console. Basically an addition to socketio/socket.io#501

lib/transports/http.js

@@ -46,7 +46,7 @@ HTTPTransport.prototype.handleRequest = function (req) {
     var buffer = ''
       , res = req.res
       , origin = req.headers.origin
-      , headers = { 'Content-Length': 1 }
+      , headers = { 'Content-Length': 1, 'Content-Type': 'text/plain; charset=UTF-8' }
       , self = this;
 
     req.on('data', function (data) {