handle Client.emit('error') events

This prevents node crashes from Client.bind() and etc.
We set a callback handler in the instance during bind()
and send errors to it.

lib/client/client.js

@@ -120,6 +120,10 @@ function Client (options) {
 
   this.log = options.log.child({ clazz: 'Client' }, true)
 
+  this.on('error', function(err) {
+    self.cb(err);
+  })
+
   this.timeout = parseInt((options.timeout || 0), 10)
   this.connectTimeout = parseInt((options.connectTimeout || 0), 10)
   this.idleTimeout = parseInt((options.idleTimeout || 0), 10)
@@ -168,6 +172,18 @@ function Client (options) {
 util.inherits(Client, EventEmitter)
 module.exports = Client
 
+/**
+ * Default handler for error callbacks when
+ * one isn't set in the instance
+ */
+Client.prototype.cb = function(err, ret) {
+  if (err) {
+    console.error('Caught exception:', err)
+  } else {
+    console.log('Unhandled output:', ret)
+  }
+}
+
 /**
  * Sends an abandon request to the LDAP server.
  *
@@ -282,6 +298,12 @@ Client.prototype.bind = function bind (name,
     controls: controls
   })
 
+  var self = this
+  this.cb = function(err, ret) {
+    delete self.cb
+    callback(err, ret)
+  }
+
   return this._send(req, [errors.LDAP_SUCCESS], null, callback, _bypass)
 }