Converts "Complete National Geographic" .cng files to CBZ.
Usage: python natgeo.py <input directory tree, where some subdirectories contain .CNG files> <output directory, where .cbz files will be placed>
Consider using Calibre to convert the CBZ files to other formats. CBZ is simply a .zip file containing plain JPEGs. If converting to PDF, paper size should generally be 7.125x10.25 inches.