Some quick fixes to make it Arch Linux (and modern distros in general) compatible

Hi, I added AUR installation information to the README.md so that users don't litter their install with package-less files (as per Arch Guidelines).

I also modified the Makefile so that it doesn't compress the man page. Distro packagers have their own methods of doing so already (and not all distros use gzip either!) and this breaks reproducible builds due to https://reproducible-builds.org/docs/source-date-epoch/ This fix will bring mtn in line with modern package specs. Thanks!