Replace C++/CLI components with P/Invoke components (#562)

* Replace C++/CLI components with P/Invoke

* Deleted C++/CLI projects

* Use Utf8StringHandle to marshal UTF-8 strings

* Use plaform-default calling convention

* Handle DLL preloading on Linux and macOS

* Change intermediate and output directories of native projects

* Improve P/Invoke documentation

AssetStudioFBXNative/utils.h

@@ -0,0 +1,29 @@
+#pragma once
+
+struct Vector3 {
+
+	float X;
+	float Y;
+	float Z;
+
+	Vector3();
+	Vector3(float x, float y, float z);
+
+};
+
+struct Quaternion {
+
+	float X;
+	float Y;
+	float Z;
+	float W;
+
+	Quaternion();
+	Quaternion(float x, float y, float z);
+	Quaternion(float x, float y, float z, float w);
+
+};
+
+Vector3 QuaternionToEuler(Quaternion q);
+
+Quaternion EulerToQuaternion(Vector3 v);