initial spock tests

I've gone ahead and written a replacement for the TestElvenArcher test using [Spock](http://spock-framework.readthedocs.org/en/latest/introduction.html). You can ignore most of it, just look at ElvenArcherSpec, and see how that compares to TestElvenArcher. 

It's much more concise, and I think much more readable. I suggest that we port over all the card tests to this style.

I also suggest that we simplify these tests. I haven't gone through them all, but in this elven archer case it seems unnecessary to have so many minions on the board, esp. the Abomination. In fact, this card and something like rifleman should have the same test as they both just let you target for 1 damage. 

Let me know what you think!