Remove RadianToDegree macro from ModelTypes

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

src/ModelTypes.h

@@ -36,6 +36,8 @@ class AnimatedTexture
 public:
 	AnimatedTexture();
 	~AnimatedTexture();
+	
+	RageVector3 RadianToDegree(RageVector3 radian);
 
 	void LoadBlank();
 	void Load(const RString &sTexOrIniFile);