Add Dariusz filtered books

I have applied to book 8moves_GM.pgn slightly modified procedure described by Martin here: http://www.tcec-chess.net/viewtopic.php?f=14&t=145 and produced cleaned up version of the book. Changes: I have used Stockfish from 31 October for analysis, checked two plies out of the book to depth 16 and assumed higher threshold +- 50 cp. Rationale: in our tests we use Stockfish in self-play so it seemed natural to use it also for analysis (I don't own H3 anyway) and at TC used in fishtest, depth of the first moves out of the book is around 16 so there is no point in enormously time-consuming analysis at higher depths, 2 plies at d16 in over 46.000 games was long enough. Threshold 50 cp seems to be a good compromise between variety and balance of the book and keeps the book with enough positions to be usable.

Some stats:
1. Original book had 49217 positions, final version shrinked to 32925 which is still big enough for all practical purposes.
2. Around 3000 positions were duplicates - either direct (rare) or just the same position out of the book but with transposed moves (a lot).
3. Number of positions found with average eval bigger than:
   +-400:      8
   +-300:     13
   +-200:     76
   +-150:    379
   +-100:   2893
   +- 50:  13200

These positions were filtered out. I have also created an epd version which is much smaller and should load quicker and be easier to use.