main: unmark game before freeing on undo
inplace: introduce global game and use it for eval

One at a time, johnny
inplace: use it for piece-square
inplace: use it for addons
inplace: use for succs
inplace: adapt {own,enemy,any}_piece functions
inplace: port move.c and move.h
inplace: use it for user_input
inplace: use it for book
genSuccs/inCheck: save global game state
inplace: search: first step
search: join exit path
inplace: search: 2nd step
inplace: search: 3rd step
inplace: search: 4th step: negamax
inplace: search: 5th step: quiesce
inplace: clean up interfaces
inplace: who knows how many-th step
inplace: search: introduce push/popGame and use them for NMH
inplace: use push/pop in negamax