The foreign repo link in the details area will display the favicon
of the foreign repo when available.
Change-Id: Id946a80beeabcd526f16872efaedbdd291444d2d
Mingle: Multimedia card #107
Image information and repo information are now both stored somewhere
else entirely, so we don't need to keep accessing weird API return
values to sort things out. fetchImageInfo now uses those classes to
an extent, and we now cache thumbnail URLs for different sizes.
Change-Id: Ife8293c86683ea914b1a5a60000584b501d92e55