* fix clippy::unused_io_amount
See related clippy documentation,
but in short some partial reads can occur
in particular with io on the networl.
read_exact/write_all transparently handle such errors.
The fix actually revealed a bug
in 'mp4a' atom parsing, but this is a dangerous change:
Parsing bugs that were transparently ignored
are now failing with error (unattended io eof).
* fix trivial clippy errors
* fix clippy error with always 0 value
* run ci/cd with clippy and latest rust version