Report errors for failed seo_cleanup renames

#451
French update

All but a few EXIF fields are updated
French update
Merge remote-tracking branch 'origin/master' into 1.4.6

Conflicts:
	zp-core/locale/fr_FR/LC_MESSAGES/zenphoto.mo
	zp-core/locale/fr_FR/LC_MESSAGES/zenphoto.po

	modified:   zp-core/admin-functions.php
	modified:   zp-core/zp-extensions/seo_cleanup.php