Version 0.4 released

Just small incremental updates. The game should be a bit easier, and the VGA fade-in/fade-out effects look great!

• The vessel is now closer to the left edge of the screen. This makes the game a bit easier as what comes ahead can be seen earlier.
• Normal platforms in the VGA version can now be non-white, as in the Tandy version.
• Implement palette-based fade in/out effects in the VGA version.
• Exit with an error message if setting the video mode fails.
• Fix french accented characters in the banner shown at exit.