private_upload 6.x-1.0-rc3

#277692 by justinrandell, stop private upload form replacing existing files

#498840 by Jody Lynn, prevent race condition bug that can misset the private file variable

#646098 by Jody Lynn, coder style fixes, uninstall function

There are still open critical issues with this module, including http://drupal.org/node/801470. This release is simply to catch up the recommended version with bug fixes that have been in the dev version for some time. (This is currently identical to the DRUPAL-6--1 dev branch)