Redhat spec

I'm maintaining a Redhat/CentOS build of mod_realdoc on Webtatic.com, and since I noticed you have a Debian spec, I've added this PR that sub-tree merges it in from https://github.com/webtatic-rpms/mod_realdoc

I was wondering if you could create a semantic version tag for the repository so packages don't need to reference git refs.

I'd also like to see if I can push this package through Fedora and EPEL