summarise_stat: fix typo
summarise_stat: handle 64b executables
summarise_stat: use a single pass & less memory
summarise_stat: be explicit about broken programs

with a dirty big "BROKEN" next to their status in the summary
and a list of broken executables after the summary.
summarise_stat: handle en_AU localised messages
summarise_stat: account for symlinks properly
summarise_stat: it is possible not to find files
summarise_stat: update copyright.