2.7.87 released May 8, 2000

- guess_mode_from_sgf_comment() removed
- coordinates (-1, -1) are now always used for pass moves (rather than
  (board_size, board_size))
- obsolete and unused debug flags marked in gnugo.h
- inclusion of sys/types.h removed from gmp.c
- unused function str2short() removed from sgf_utils.c
- cleanup of play_solo.c, play_test.c, and sgf_utils.c
- bugfix: move number again passed from the interfaces to the engine