Remove ".dll" suffix from LoadModule calls.

Created by: Kaffeine

Remove ".dll" suffix from LoadModule calls.

The final goal is to make LoadModule calls platform-independent (we have ".dll" on Windows and ".so" on Linux/Mac)

https://github.com/OpenXRay/xray-16/blob/ai_cleanup/src/xrEngine/EngineAPI.cpp#L135 and so on.

Note: we need to verify that the game works with the changes.