Eden and Frodo compatibility added

XBMC Frodo now provides thumbs and posters with .jpg extension instead of Eden's .tbn extension. the code now checks first for Eden's and then for Frodo's extensions.
Eden and Frodo compatibility added

XBMC Frodo now provides thumbs and posters with .jpg extension instead of Eden's .tbn extension. the code now checks first for Eden's and then for Frodo's extensions. additionally, it looks for posters and banners without the "folder" prefix to increase compatibility.
Merge pull request #4 from pancheto/master

Eden and Frodo compatibility added