Generic cleanups

- hunt for more hardcoded variant-specific constants
  - position of captured pieces in curses mode
  - compile with bound-checker
- add autosave mode to ease hunt for segfaults ?
- generate patterns.inc at build-time
- use 2D array for the board, get rid of the (i)nunmap stuff
- fixup build procedure to support parallel make runs
- investigate those preexisting "overflow in implicit constant
  conversion" warnings

Minishogi-related stuff

- make minishogi a run-time option rather than a compile-time one
- minishogi patterns
- tune difficulty levels
- other tunings to investigate
  * PromotionZoneDistanceBonus
  * OPENING_HINT
- add minishogi stuff to the doc
- use valid minishogi moves in online help

- segfault (on level 1) following 2e1d 1d4a
	=> field.piece can reach 14 in pattern.c::update_advance_bonus
	   => probably related to using patterns for standard shogi
	   => must break the circular pattern.o <-> pattern.inc dep to
		be able to generated pattern.inc as needed