Implement Dungeon Master and Nira, Hellkite Duelist

[jmharmon]

This for completion of the set, since Chandra, Gremlin Wrangler is already implemented.

[JayDi85]

Use DungeonMasterSkeletonToken or Skeleton2Token name styles, not SkeletonToken2.

[JayDi85]

You can use game.getOpponents(source.getControllerId())

[JayDi85]

Use xmage's RandomUtil.nextInt(), not java

[JayDi85]

I don't think it's correct to use random ability in constructor. There are special cards to work with roll dice events like As Luck Would Have It . Some of that cards can change roll dice result like Krark's Other Thumb. And that's all are in-game events with user dialogs -- it's can't be in constructor.

That's why I recommend change random to player.rollDice action and calls it from enters battlefield trigger ability/effect

[jmharmon]

Use DungeonMasterSkeletonToken or Skeleton2Token name styles, not SkeletonToken2.

I was following file naming that we have already if there's multiple tokens of the same creature type. For example, we have BeastToken, BeastToken2, BeastToken3, and BeastToken4.