debian/copyright: Silence lintian warning

Due to word wrapping, lintian issues the following:

W: alac source: syntax-error-in-dep5-copyright

After fixing word wrapping, lintian issues the following warning:

W: alac source: comma-separated-files-in-dep5-copyright

Files in debian/copyright are seperated by whitespaces, for future reference.
alacconvert.1: Fix style, delete useless comments, and other roff stuff
debian: Add alacconvert.install/manpages

Forgot to do it before. Silences lintian empty-binary-package warning.