Update GLM to latest version (0.9.9.3). This includes GLM's change of matrices no longer default initializing to the identity matrix. This commit thus also includes the update of all of LearnOpenGL's code to reflect this: all matrices are now constructor-initialized to the identity matrix where relevant.

includes/glm/ext/vector_double1_precision.hpp

@@ -0,0 +1,36 @@
+/// @ref ext_vector_double1_precision
+/// @file glm/ext/vector_double1_precision.hpp
+///
+/// @defgroup ext_vector_double1_precision GLM_EXT_vector_double1_precision
+/// @ingroup ext
+///
+/// Exposes highp_dvec1, mediump_dvec1 and lowp_dvec1 types.
+///
+/// Include <glm/ext/vector_double1_precision.hpp> to use the features of this extension.
+///
+/// @see ext_vector_double1
+
+#pragma once
+
+#include "../detail/type_vec1.hpp"
+
+#if GLM_MESSAGES == GLM_ENABLE && !defined(GLM_EXT_INCLUDED)
+#	pragma message("GLM: GLM_EXT_vector_double1_precision extension included")
+#endif
+
+namespace glm
+{
+	/// @addtogroup ext_vector_double1_precision
+	/// @{
+
+	/// 1 component vector of double-precision floating-point numbers using high precision arithmetic in term of ULPs.
+	typedef vec<1, double, highp>		highp_dvec1;
+
+	/// 1 component vector of double-precision floating-point numbers using medium precision arithmetic in term of ULPs.
+	typedef vec<1, double, mediump>		mediump_dvec1;
+
+	/// 1 component vector of double-precision floating-point numbers using low precision arithmetic in term of ULPs.
+	typedef vec<1, double, lowp>		lowp_dvec1;
+
+	/// @}
+}//namespace glm