[development] patches that need reviews/work

[andrew morton]

This issue is concerned with making files into a proper Drupal object,
on par with nodes, users or comments. Currently, it does a few things:
- adds file_load() and file_save() functions.
- adds a hook_file to provide notice of file events.
- refactors the file functions to track files in the database.

It's still at a formative stage so if you've got strong feelings about
file handling please weigh in:
http://drupal.org/node/142995

andrew