Add some information about used compiler, and available threads.

Compile with:
$ ghc -o brickoku-game -O -threaded -rtsopts brickoku-game.hs

Then run with:

./brickoku-game +RTS -sstderr -N3

Note, no use of threads yet, but interesting to see this info anyway.
Use prefix and braces to show bit more clear what was intended.
Output for work on solving puzzles.
Added: renderer for possibilities.