l3ib/nitrogen — pull request #30 by EvanPurkhiser (2013-06-16 23:17:50+00:00)
Title: Follow the Freedesktop spec for thumbnail location

According to the [Freedesktop specifications for thumbnails](http://specifications.freedesktop.org/thumbnail-spec/thumbnail-spec-latest.html#DIRECTORY), the thumbnails directory should be stored in `$XDG_CACHE_HOME/thumbnails`, not in `$HOME/.thumbnails`. This fixes that.