Target for v1.5:

- make X and raw two different display drivers
- integrate H.G.Muller's work on the xboard protocol on top of new driver-like
  display handling
- deprecate xshogi in favor of xboard
- make minishogi a run-time option rather than a compile-time one,
  using the "variant" mechanism of the xboard protocol

Generic cleanups

- switch cli parsing to getopt
- hunt for extern's and prototypes spread all over the source
- 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 ?
- ? 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

- 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

Improvements

- find out why the engine is so weak
  - make it battle against Mutz-era gnushogi, and other engines, and
    compare their evaluation results
  - see what needs updating in book