I am no longer supporting this app as the disk-caching was added in iOS 5. Somehow it slipped under my radar, which is why I developed this library in the first place during the iOS5 era.
More information about native disk caching can be found on the following post over at Peter Steinberger's Blog.
The codebase will remain online and available for now. The old readme can be found in the README_OLD.md file.