Remove RadianToDegree macro from ModelTypes

We can remove two macros from RageMath which are only used in a single place.

src/ModelTypes.cpp

@@ -29,6 +29,23 @@ AnimatedTexture::~AnimatedTexture()
 	Unload();
 }
 
+RageVector3 RadianToDegree(RageVector3 radian)
+{
+	// This is more accurate than the original SM5 implementation,
+	// but that raises a double-to-float mismatch warning, so this
+	// prevents that issue from occurring.
+	//
+	// A way to implement the original code exactly would be:
+	//
+	// RageVector3 radian = { radian.x * (180.0f / PI) };
+
+	return RageVector3(
+		static_cast<float>(radian.x * (180.0f / PI)),
+		static_cast<float>(radian.y * (180.0f / PI)),
+		static_cast<float>(radian.z * (180.0f / PI))
+	);
+}
+
 void AnimatedTexture::LoadBlank()
 {
 	AnimatedTextureState state(