Implement Griffon piece type

Implement Griffon piece type

Four new RiderTypes are added, using 'tableless magics'. Thai is, they
use the attacks tables of the Rook, but shifted by one file or rank.
The Betza parser in extended to recognize two-leg moves of teh type yafs...,
where yafsF is recognized as the Griffon. It then generates the (fake)
large leap that is used to indicate these type of bent slides, omitting
moves to the first square of the ride. (Because this is what yafsF means).
  Unbent moves of the type yaf... are recognized as lame ski-sliders.