1) 6.20 drupal checks inside image_get_info() that the file is an uploaded file or not, so the validation filefield_validate_is_image() will almost fail. so replacing it with FIG's own is_image validator.
2) FeedsEnclosure class deletes the downloaded file in its destructor, so expanding its life span (feels like god!!).

#756470 by publicmind: Append the filename with its extension if not already present and if it is an image.

#974226 by publicmind: Checking the $result for headers key, before doing any operation in order to prevent the warning thrown.

bug #882992 by publicmind: changing the HTTP headers to all lower case as some servers do not respect the case while returning header array.

feature #857980 by dman, publicmind: Added support for putting library files like url_to_absolute.php in either modules directory or libraries folder. Integrated with 'libraries' module as well.

#763196: removed 'length' paramenter from 'int' type.

#731798 by publicmind: fixed encoding of urls, encode_url function to be added in UrlToAbsolute package on SF.net

helper functions ported from D7 branch, drupal_http_request ported as well to feeds_imagegrabber_http_request (nice timeout feature)