Minor changes to math module

-Fixed missing Set method: "X::Set(const X&)"
-Removed operator String


Former-commit-id: 690f161704ed85fc57a62b812af7933e390572b5

include/Nazara/Math/Quaternion.hpp

@@ -57,8 +57,6 @@ template<typename T> class NzQuaternion
 		//NzMatrix3<T> ToRotationMatrix() const;
 		NzString ToString() const;
 
-		operator NzString() const;
-
 		NzQuaternion& operator=(const NzQuaternion& quat);
 
 		NzQuaternion operator+(const NzQuaternion& quat) const;