Increase the pool of fd's for httpproxy

1K should be fine as long as user's ulimit is not too low, but we set the ulimit
for user in the install script, so it should be fine.

tools/run-httpproxy.js

@@ -44,7 +44,7 @@ _.extend(HttpProxy.prototype, {
     self.proxy = httpProxy.createProxyServer({
       // agent is required to handle keep-alive, and http-proxy 1.0 is a little
       // buggy without it: https://github.com/nodejitsu/node-http-proxy/pull/488
-      agent: new http.Agent({ maxSockets: 100 }),
+      agent: new http.Agent({ maxSockets: 1000 }),
       xfwd: false //true
     });