pattern_rate_moves(): Add a debug print listing all patterns considered
sgf2gtp.py: Default SZ to 19
Consider a tree during which we drop komi as untrustworthy - don't resign or reuse it

In late endgame, raising a komi by 1pt can fatally destroy the tree.

Problem discovered in KGS pachi-Marknguyen on 2013-12-13.