add socket error-handling. Closes #6

otherwise node just explodes, not a good default

lib/application.js

@@ -119,11 +119,14 @@ app.context = function(obj){
 app.callback = function(){
   var mw = [respond].concat(this.middleware);
   var fn = compose(mw)(downstream);
+  var onerror = this.onerror.bind(this);
   var self = this;
 
   return function(req, res){
     var ctx = new self.Context(self, req, res);
 
+    ctx.socket.on('error', onerror);
+
     function done(err) {
       if (err) ctx.onerror(err);
     }