Check Collection: are all subobjects working correctly?

Add support for query caching server configuration.

Check all of the docs: create section of inherited methods in each submodule.
Add more examples.

Add module "Tree" for handling a tree of HTML files.

Add module "EZMLM" for handling all the messages in an ezmlm archive.

Add module "MHonArc" for handling all the messages in a MHonArc archive.

Add module "Mailman" for handling all the messages in a Mailman archive.

Add module "PDF" for handling PDF documents, probably based on standard Perl
modules for handling PDF.

Add module "Thread" for adding processor routines that automatically create
threading information, optionally stored in a backend such as Storable or
an SQL database.

Add ultralite parameter support to NexTrieve::Resource.

Add "hints" method for finding out what could be done to improve the
performance of a module and all of its submodules, e.g. to load and install
the Text::Iconv module for recoding.

Create text processing routine for RFC822 that would create commented text and
footer information.
