This is a simple example of a cartridge loader. This class needs to provide access to files within a cartridge. The
parser DOES NOT CARE HOW. In this case, we assume that a zip file is given to us, which we unzip into the specified
directory or the system temp directory. We don't clean up after ourselves.
Implementers will need to provide a cartridge loader of their own, which can return files from cartridges to the parser,
as requested. The parser uses paths and filenames from the manifest. If a file cannot be found, then an exception should
Another example of a loader can be found in the test code (TestLoader).