Slight modifications
Slight modifications

- Updated addCallback such that synchronous errors (for instance,
  no backing LDAP connection) are passed into the error object of
  the callback
- Passes jshint, now.

jeremycx/node-LDAP,jeremycx/node-LDAP,wavify/node-LDAP,jeremycx/node-LDAP,wavify/node-LDAP,jeremycx/node-LDAP,wavify/node-LDAP,wavify/node-LDAP