Moar updates!

c2048_ai.c:
- added _rowscore_weights for BOARD_SIZE == 5
  added script make_rowscore_weights for so you
  can make any BOARD_SIZE you fancy.

main.c:
- added direction counter

make_rowscore_weights.py:
- script that makes rowscore_weights for any
  BOARD_SIZE you'd fancy.