use theme functions to format blocks à la Drupal instead of hand-rolled HTML

there should be a (per-user) setting for the maximum length of HD blocks before paging occurs: lists are currently unlimited

there should be a site-wide setting for these values, acting as a default prior to user settings

a HD user can define whether (s)he wants one of the blocks made available by the module on his pages. A per-user setting could be added to define whether users wanting the blocks want them whether they are empty or not.