"--version" produces too much output

[ruafozy]

"--version", if generated with Methadone::Main#version, causes the entire
usage message to be output. This is against Unix conventions.

By way of comparison, consider the output of "ruby --version", "python
--version", "perl --version", or "ls --version".

The GNU coding standards specify the behaviour of "--version":

http://www.gnu.org/prep/standards/html_node/_002d_002dversion.html#g_t_002d_002dversion

[ruafozy]

Granted, it's probably impractical to have #version
implement the GNU coding standards. Instead, I think
it should copy Python, and simply give the application's
name and its version string.

[davetron5000]

This will be in the next release, see 1932c82