stdin behaviour is difference

Behaviour of snzip is difference with other same kind command such as bzip2 or gzip.

$ cat test.txt.bz2 | bzip2 -d
foo bar baz

$ cat test.txt.sz | ./snzip -d  # different behaviour!!!
I won't write compressed data to a terminal.
For help, type: 'snzip -h'.
When the command use with stdin, only snzip complain.

https://github.com/kubo/snzip/pull/4