At the moment, there’s nothing for DKs in this patch. I suspect and hope it means Blizzard are still rejigging our rune mechanics, about which beta testers have given plenty of constructive (albeit negative) feedback.
Masteries are not implemented in this beta version. See my embedded video for Gravity in mastery-stat gear, which uses ugly placeholder material, and a few death strikes that do nothing special at 0:56 onward.
The spells are in the game files, but you can’t use them.
In case something turns up, we’ll report on it in the patch thread.