Patch to use Drupal.behaviors instead of $(document).ready

Currently Hovertip uses $(document).ready to load itself. This is not the standard Drupal way to load javascript, as it does not work on content loaded using AHAH. As a result, the current Hovertip version does not work on content loaded using AHAH. See http://drupal.org/node/205296

This patch changes the use of $(document).ready to the Drupal way using Drupal.behaviors.

I've also updated all behaviour attach calls to avoid duplicate attachments.

Greetings,
Hylke