Retrieve remote resources like GATK/MuTect jars present in S3.

def _add_remote_resources(resources):
    """Retrieve remote resources like GATK/MuTect jars present in S3.
    """
    out = copy.deepcopy(resources)
    for prog, info in resources.items():
        for key, val in info.items():
            if key == "jar" and objectstore.is_remote(val):
                store_dir = utils.safe_makedir(os.path.join(os.getcwd(), "inputs", "jars", prog))
                fname = objectstore.download(val, store_dir, store_dir)
                version_file = os.path.join(store_dir, "version.txt")
                if not utils.file_exists(version_file):
                    version = install.get_gatk_jar_version(prog, fname)
                    with open(version_file, "w") as out_handle:
                        out_handle.write(version)
                else:
                    with open(version_file) as in_handle:
                        version = in_handle.read().strip()
                del out[prog][key]
                out[prog]["dir"] = store_dir
                out[prog]["version"] = version
    return out