add the possibility to reset the loaded picture by loading the null URL
add some comments in the code
rename CacheType to LifeSpan
make an enum for the storage file format (StorageType)
move the transforms in separate packages for more clarity/readability
cleaning
move the default loaders in a package for more discoverability
simplify setLoadingURL() so that the PictureLoaderHandler doesn't need to know about DownloadManager