Lots of cool additions

This update brings lots of little things that make the game more polished... and way cooler!

CHANGELOG

• Added bouncing arrow that indicates the active soldier in the entrance area.
• Made "I'm ready" walkie-talkie-style speech sample play when a new soldier becomes active.
• Added soldier death effect (when a soldier is killed, it will remain lying dead on the ground, and his soul will fly to Heaven).
• Reworked Exxwor enemy sound samples.
• Added wide arch tile.
• Touched up arenas.
• Made other internal improvements/bugfixes.