split looping write thread from packet writing
describe file.c functions better
cleaned up file.c typo
compression sequence cannot have 0 for length
read in file bytes via read_dogfile

file.c got quite complicated here. added filebufs
and plenty of helper fns like sample_cpy and
extend_buffer, an overflow buffer

closes #9
update reviewer to use read_dogfile
start parsing meta header for 'compressed' key
define a few lossy levels to choose from
give write_packet dogfile, check compression field
check compression when reading df, before expand
read in lossiness from df header
create df, set compression and lossy level
add top info line to review image
filename and comp/lossy into meta rvw row