Update changelog and bootanimation

 - Original bootanimation by Kiernan Moore (http://www.youtube.com/watch?v=KtAcw6rRFQ0)
 - "Powered by Android" mod by sgosiaco (http://forum.xda-developers.com/google-nexus-5/themes-apps/bootanimation-nexus-5-powered-android-t2697912)