Updating SFML to 2.3

[Pranav Kant]

I unorphaned SFML couple of days back. I plan to update the version to
latest upstream version, SFML 2.3 in f21, f22 and rawhide.

Affected package : marsshooter
$ repoquery --whatrequires SFML SFML-devel
marsshooter

To build marsshooter against latest SFML, a small patch is required.
My sponsor Mamoru, as provenpackager, will take care of fixing
marsshooter build against latest SFML.

-- 
Regards,
Pranav Kant,
http://pranavk.me