core: Prepare NEWS file for release 0.4.6
core: Prepare NEWS file for release 0.4.6

jku/rygel,GNOME/rygel,luisbg/rygel,Pelagicore/Media-Manager-Rygel-patched,GNOME/rygel,GNOME/rygel,Tarnyko/rygel,jku/rygel,Pelagicore/Media-Manager-Rygel-patched,Pelagicore/Media-Manager-Rygel-patched,Tarnyko/rygel