FU r100535:

FU r100535:
* Added thumb-handler.php5 file
* Moved 404.php to thumb-handler.php as wfDisplay404Error()
* Removed excess short-circuiting error cases in thumb-handler.php
* Moved cURL extension check to the top of the file
* Improved sample $thgThumbHashFragment regex value
* Cleaned up wfStreamThumbViaCurl() error handling code a bit