wordpress metabox [upload] resources and tutorials
- http://tommcfarlin.com/wordpress-upload-meta-box/
- https://github.com/tommcfarlin/WordPress-Upload-Meta-Box
- http://themefoundation.com/wordpress-meta-boxes-guide/
- http://wp.tutsplus.com/tutorials/attaching-files-to-your-posts-using-wordpress-custom-meta-boxes-part-1/
- http://wp.tutsplus.com/tutorials/attaching-files-to-your-posts-using-wordpress-custom-meta-boxes-part-2/