Clean up doxygen documentation

glm/core/type_half.hpp

@@ -39,8 +39,6 @@ namespace detail
 	float toFloat32(hdata value);
 	hdata toFloat16(float const & value);
 
-	/// 16-bit floating point type.
-	/// @ingroup gtc_half_float
 	class half
 	{
 	public: 

glm/gtc/quaternion.hpp

@@ -50,9 +50,6 @@
 namespace glm{
 namespace detail
 {
-	/// @brief Template for quaternion. 
-	/// @see gtc_quaternion
-	/// @ingroup gtc_quaternion
 	template <typename T> 
 	struct tquat// : public genType<T, tquat>
 	{