finish CKMesh writing (no test)

- finish CKMesh writing function
- remove useless CKMesh functions: material channels, vertex weight and face mask.

LibCmo/VxMath/VxMath.cpp

@@ -1,7 +1,7 @@
 #include "VxMath.hpp"
+#include <cmath>
 #include "stb_image_resize.h"
 
-
 namespace LibCmo::VxMath {
 
 #pragma region Structure copying
@@ -149,6 +149,12 @@ namespace LibCmo::VxMath {
 			);
 		}
 
+		void Abs(VxVector3& lhs) {
+			lhs.x = std::fabs(lhs.x);
+			lhs.y = std::fabs(lhs.y);
+			lhs.z = std::fabs(lhs.z);
+		}
+
 	}
 
 #pragma endregion

LibCmo/VxMath/VxMath.hpp

@@ -93,6 +93,8 @@ namespace LibCmo::VxMath {
 		CKFLOAT DotProduct(const VxVector4& lhs, const VxVector4& rhs);
 
 		VxVector3 CrossProduct(const VxVector3& lhs, const VxVector3& rhs);
+		
+		void Abs(VxVector3& lhs);
 
 	}