Hitori. One infrastructure change in the process: latin.c has
acquired a utility function to generate a latin rectangle rather
than a full square.
[originally from svn r8828]
introduced to mimic similar macros in solo.c, in case Solo ever
moved over to being based on the latin.c solver framework; but even
Solo has long since lost those macros, so latin.c has no need to
keep them.
[originally from svn r8827]
programs having to clone the latin_solver() function and insert
their own extra deduction routines, they can now just _call_
latin_solver with enough parameters to let it fit its own deductions
into their difficulty framework and call a set of provided function
pointers to do user deductions. Modified Unequal to work in the new
world, of course.
[originally from svn r8791]
