* some minor cleanups to .info and .install switched package to ImageCache and...

* some minor cleanups to .info and .install switched package to ImageCache and module name to ImageCache.
* backported header responses from 2.x.
* added some good watchdogs and more error checking/reporting.
* cleaned up lock/tmp file handling. register_shutdown_function is my friend.
* removed some cruftiness from the processing loop and race handling.
* new tmp filename tmp_imagecache_{md5(src)}_{preset}_{basename(src)}, so they are guaranteed unique and mostly identifiable.
* removed optional use of mime_content_type.
* added 307 Location header for images already being process to cause reload of current page... This should try to reload a few times hopefully giving us enough time to finish processing the image.