New Maps and Some Optimizations! OCT 19 Update

1. Added 2 new PvP maps, Fight for Every Inch, and Beacon Fire Everywhere.
2. Fixed an issue that units may get stuck when using Spear Wall Charge and Shield Wall Charge.
3. Frontline Spearmen's cost is reduced to 800, and Spear Wall Charge's upgrade cost is reduced.
4. Vanguard's cost is reduced to 800, and Shield Wall Charge's upgrade cost is reduced.
5. Updated some sandbox materials.
6. Performance optimization.