Allow encoding of non-contiguous slider ranges

Allow encoding of non-contiguous slider ranges

The range of sliders as encoded in the steps/slidrs/hoppers maps
that are passed from the Betza parser to the attack bitboard generators
are no longer encoded as a number that indicates the range, but as the set
of squares along the ray. Each of the lower 16 bits in this parameter
corresponds to such a square, and setting the bit would deny access to that
by keeping it out of the pseudoMoves/Attacks bitboards. So a range-3
slider would need code 0xFFF8, range 4 0xFFF0 etc.
  This opens the possibility to encode lame ski-sliders by passing a 1,
excluding the first square on the ray as destination. (But keeping it
as a potential blocking square of the entire slide. Or lame riders like
the Dabbabarider (0x5555) or lame Panda (0xAAAAA), in combination with
the Rook magics.
  This does not affect leapers, which keep using a 1 code for encoding
lameness.
  Note that although non-contiguous destinations can currently break
FSF's check detection, leading to crashes. This occurs with sliders that
can deliver check by moving radially away from the King, such as lame
ski-sliders. Lame elemntary riders (DD, AA, HH) should be OK.