Rpm specs

I build some RPM packages for RedHat based distributions (Fedora, Scientific Linux). I wasn't sure if you want to have distribution specific code in your wiki so I put the documentation in this new branch.
- The .spec file is the “blueprint” for the RPM build process
- I put some ready-to-use RPMs up on Google Drive (accessible to anyone)
- The …/rpm/readme.md contains links to all pre-build and source packages as well as some further instructions.

Feel free to integrate them in your documentation or reject them.