A new stage and ten new arenas to enjoy!

This build represents a major step as it adds lots of content and brings quite a number of additional improvements.

CHANGELOG

• Added stage THE WAREHOUSE (previously THE CELLARS/JAILS).
• Added 8 arenas.
• Added milestone bonus (a soldier is awarded every 20000 points).
• Reduced number of wors to kill per stage.
• Refined rendering of blast marks, so that they follow the irregular borders of the nearby vertical tiles.
• Reduced shadows to 2 bits to make them sharper and stay more faithful to 16 bit machines.
• Touched up / redrawn a few tiles.
• Updated/improved manual.
• Made a couple of minor bugfixes.