made file path detection more robust - this can probably be pared down a bit later
added __bytes__() magic methods where needed to lay the groundwork for generating new packets instead of only reading them
copied test_FileLoader.py over from debutils
copied these two files over from Debutils for testing FileLoader
front-loaded the file loading to prevent a sync issue with comparing the files - was seeing a situation where I would download the Debian-sid Release.gpg file to parse, then download again to check against pgpdump, and pgpdump would get a newer version.
simplified bytes_to_int and int_to_bytes; added the ability for int_to_bytes to zero pad