Added the Bratko-Kopec tests (commented out) to puzzles

The tests from http://chessprogramming.wikispaces.com/Bratko-Kopec+Test
were added to the `puzzle` unit test. We only passed the first one, the
rest is currently disabled.

I didn't implement the parser for the Extended Position Description
(http://chessprogramming.wikispaces.com/Extended+Position+Description),
so we don't accept multiple solutions, and also can't handle "avoid
move" cases.
Fix move legality check. We can block ray attacks..