more tests/test material modifications
 - modified the header in compressed.08 to use a one-byte length instead of an indeterminate length
 - changed the keyserver in signature.0x18 to fakekey.server.tld
 - modified the parametrization of packet headers and parsing tests to append CAFEBABE to the end of each packet as a sentinel value to ensure that none of the parsed packets are being overly greedy; modified the tests to take this into account
 - filled out all missing pgpdump strings for subpackets
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 - renamed subpacket and packet files to be more easily eye-sortable
 - updated parametrizations to match the new filenames
 - disabled stdout capturing in py.test
 - added classname output to TestPacket.test_load
added a new userid packet that found a problem with my uid regex
fixed parsing errors discovered by test_load_paul_pubring:
 - not all length fields are the appropriate length for their contents (i.e. 5 byte lengths for values that fit in 1 or 2 byte lengths), so subpacket parsing now counts how many bytes were parsed rather than the length of all current subpackets
 - moved byte-popping for length fields to the header parsing function
 - updated uid regex to work with more things
 - added support for indeterminate packet lengths in old format headers