#133 OpeningTree is not fast enough to follow game browsing

[Bruno Rizzuti]

The following happens with a database that requires for OpeningTree a few tenths of seconds to update (20 games are sufficient on my system):

when a game is rapidly browsed (e.g., selecting the first move in GameText and keeping right-arrow key pushed), the final move that appears in OpeningTree is a move that in reality has been played somewhere in between the game;

also the other way around: selecting the last move in GameText and keeping left-arrow key pushed, the final move that appears in OpeningTree is not the first move (and also the list in GameList goes astray).

[Bruno Rizzuti]

Fixed with commit #989