Revert 7d4613e7a820c3fcb775c40ae142ca7c6f646ab1 and clean up wpsc_item_process_file a wee bit.  Not sure what I was smoking in #688, but it better have been worth the price of admission.  Fixes #1248
Merge branch 'master' of github.com:wp-e-commerce/WP-e-Commerce