Please checkout the change to enable building fcgiwrap as RPM package

Hi gnosek,
  Thank you for your excellent FastCGI tool! I use it to serve Gitolite/cgit behind Apache or nginx.
  I come up .spec file to enable fcgiwrap to be built as an RPM package. It builds a systemd enabled RPM on OS like Fedora 14+, RHEL 7. The RPM on these platforms enables and start the fcgiwrap.socket. It's a lot more convenient for admin as they no longer need spawn-fcgi or equivalent.

  I also updated the README to mention the systemd socket activation feature and add instructions to build the RPM package.

  I have tested RPM package on CentOS 6.4, Federo 20 and Pidora (Federo 18 on Raspberry PI). 

  Could please take a look at this pull request and consider merge it into main line?

  Thanks a lot!