support non-ascii pdf thumbnails in windows
support non-ascii pdf thumbnails in windows

for non supported filenames use memory loader except for files > 100 MB
(use temporary file for those)

meganz/sdk,meganz/sdk,Acidburn0zzz/sdk,Acidburn0zzz/sdk,Acidburn0zzz/sdk,meganz/sdk,Acidburn0zzz/sdk,Acidburn0zzz/sdk,meganz/sdk,meganz/sdk,meganz/sdk,Acidburn0zzz/sdk,meganz/sdk,Acidburn0zzz/sdk,Acidburn0zzz/sdk