PhaseBeamSelector: Make license of that file clearer

- Brings back license of the original unmodified file
- GPLv3 applies only to the changes made by myself in
  the previous commits to this file

Change-Id: Iafe166c8836da5f86b7c166518f5e6c84fc8dbac
Merge branch 'android-4.3' of https://github.com/omnirom/android_packages_wallpapers_PhaseBeam into android-4.3