Replacing upload with flash-based approach.
Rendering alerts and removing debugging.
Fixing flash overlay size/z-index issues with delete modal.
Actually returning file metadata after uploading files.
Using file upload response to update filestore collection.

Also fixing error messages for uploads.
Merge branch 'flash-upload'. Replaces previous native uploader with one that uses a Flash-based shim.

Shim allows upload progress updates, and so resolves #46.
Fixing error message for file uploads in IE8.