Improve millennium_auth module

First stab at this.

• It works on OPACs that have HTTPS authentication.
• Works on OPACs that have 3 fields (name, code, pin) and 2 fields (name and code). I need to find out if there are other combinations (e.g. name + pin, code + pin?) or maybe even other field names.
• Gets current checkouts, fines, total number of holds + number of holds "ready to pickup".

Todo:: lots:

• Test on more OPACs (need to partner up with more libraries)
• New Drupal users that are created have no email (the approach could be to automatically add an email address from parts of the login, user data, etc with a default domain configured by the admin)
• See if we could do fancy things like share no/some/all personal data like checkouts, or have a "private" RSS feed of items visible only to those who know a special URL)

New patch, will commit this soon.

* Holds and checked-out items list works on more OPACs.
* Added option on user/XXX/edit to let users select whether they want to share their checkouts on ther profile (user/XXX) page.
* Now encrypt some of the stored information with basic 2-way encryption (low security, but better than none)
* Caching did not properly check for staleness, fixed.

TODOs:
* Write some docs for this module
* Remove the "experimental" messages from the module .info?

This has been committed.

See http://drupalcode.org/project/millennium.git/commit/710f24a