v1.31 Test Version Update：

Features:
- New Feature: auto-sort function for player’s inventory can be turned on/off in the Store.
Optimization: 
- Customized trajectories for each bullet type, in order to improve graphics.
- Removed the option to attach a silencer to SV98M and Thompson.
Bug fixes: 
- Duplicating item when equipping the soldier from Special Item Slot.
- Soldiers occasionally spawned under the ground, in the bandit camp map.
- Occasionally showing tutorial text when activating hint windows.