KDE Licensing Policy Changes

Today I updated the KDE Licensing Policy with a couple of changes following requests from folks. Most notably Creative Commons is now allowed. This is only for standalone media files (such as an image for a splash screen) and not for anything which might want to be mixed with GPL material such as icons. "Attribution-Share Alike 3.0 Unported" is the version allowed. The other change is requiring BSD licencing for CMake modules, which brings the policy into line with existing practice.