Update handlers.

Here are some required updates:

1. For all of the user defined handlers we need to add AJAX support to be able to select nodes/terms/users from auto complete list. If JavaScript is disabled we need to allow user to enter them manually.
2. For the random handlers we need to be able to selelct:
   • Content types for nodes
   • Vocabularies for terms
   • Roles for users
3. We need to check access permissions for nodes/terms and users.