Patch - Improves code and UI for better engine stability - V14.5.30

Addresses minor issues across the engine to improve stability and UI.

- Updates ImGui window size for better rendering
- Adds macro for boolean returns (R_TRUE and R_FALSE)
- Adds missing includes and removes unused code
- Updates shader code to use the new macros and improve readability

enginecustom/src/inc/system/application_class.h

@@ -63,8 +63,6 @@
 // GLOBALS //
 /////////////
 constexpr bool full_screen = false;
-// constexpr float screen_depth = 1000.0f;
-// constexpr float screen_near = 0.3f;
 
 static std::map<std::string, std::shared_ptr<model_class>> g_model_cache;