refactoring: rename "one move back/forward" to "previous/next board position"
refactoring: rename "one move back/forward" to "previous/next board position"

herzbube/littlego,herzbube/littlego,herzbube/littlego,herzbube/littlego,puremourning/littlego,puremourning/littlego,puremourning/littlego,puremourning/littlego,herzbube/littlego