Update SuperTux to 0.6.2

Changes:

• A new worldmap, “Revenge In Redmond” celebrating SuperTux’s 20th anniversary, which includes new enemies and sprites
• New and improved backgrounds and sprites
• Improvements to many levels in the Icy Island and forest world
• Speed improvements for levels using a huge amount of lava tiles
• An issue causing the bridge in the forest world to not be shown in certain cases was fixed

Loaded my saved game, played through a whole level, downloaded and played a level from an add-on, launched the level editor