Update functions_bmz_io.php

Use a friendly name instead of the very ugly md5 hash names.
Update bmz_image_handler.class.php

Use a friendly name instead of the very ugly md5 hash names
Update README.md
Activate error messages

Per this post:

http://www.zen-cart.com/showthread.php?215296-Corrupted-product-database-entry-leads-to-blank-product-listings&p=1265509#post1265509
Merge pull request #2 from DivaVocals/master

IH