Update ldapjs / Node 6 support

Update ldapjs to 1.0.1 and allow patch updates without re-releasing.

groupSearchFilter can be a function

groupSearchFilter can be a function that receives the LDAP user object and returns the actual search filter.

var  opts = {
  ...
  groupSearchFilter : function(user) {
    return "(member={{uid}})".replace(user.dn);
  };
};