Up keepalive timeout.

This will cause it to take a little longer before an abandoned server dies and frees it's port, but should reduce accidental deaths when the supervising process is backlogged.

app/server/server.js

@@ -30,7 +30,7 @@ var init_keepalive = function () {
 
   setInterval(function () {
     keepalive_count ++;
-    if (keepalive_count >= 2) {
+    if (keepalive_count >= 3) {
       console.log("Failed to receive keepalive! Exiting.");
       process.exit(1);
     }