Gives the games tree panel space for games with longer names via horizontal scrollbar. Fixes issue with error messages in estimate panel appearing in blue instead of red.
Entirely removes GamesTreePanel because it was an unnecessary middle man. Also reworked the GameTree class so it isn't a scrollpane (which is was for some reason)

Old format = JTree within a scrollpane within a panel within a scrollpane within a panel within a panel
Updated format = JTree within a scrollpane within a panel within a panel

Also removes old GameTrees when refresh is called. An instance of a GameTree was being created whenever refresh was being called, the old ones were just being cut off by the panel size, so we never noticed.
Now refresh correctly removes the outdated GameTree if there is one.