filefield 6.x-3.0-alpha3

This release introduces more cleanups and ajax uploads for filefield. There are still a few blocker to moving up to beta. The current beta blockers are the upgrade path, and deleting removes files on node save.

Changes since DRUPAL-6--3-0-ALPHA-2:

• #286834 by quicksketch and dopry, so AHAH was in place... If you're using ahah make sure your wrapper id exists, otherwise stuff can be a real mess. Also the jQuery form plugin does file submission in an iFrame and you can't trust the post in the network console. I had to put the ahah wrapper in #prefix/#suffix and they have to be overridden in the JS callback to prevent duplicate div wrappers appearing... I kind of wish ahah replaced it's wrapper rather than inserting inside the wrapper. ce la vie. but here is working JS upload and remove.
• #293977 by Amitaibu, fix 404 errors on file view, typo in filefield's hook_file_download.
• implement per node/field max cumulative filesize validation.
• dodge devel.module errors... I still really hate that I can't send the application/javascript content type... I'm gonna track that bug down one day.
• fix max filesizer per node validation, if max_size is not set do not check.
• remove unnecessary submit callback for remove_btn.
  reset item to default value when remove is selected instead of just changing fid to 0 so description field gets erased.