Use Imgui integrated opengl loader

src/main.cpp

@@ -6,11 +6,13 @@
 #include "imgui.h"
 #include "backends/imgui_impl_glfw.h"
 #include "backends/imgui_impl_opengl3.h"
-#include <GL/glew.h>
 #include <stdio.h>
 #if defined(IMGUI_IMPL_OPENGL_ES2)
 #include <GLES2/gl2.h>
 #endif
+#ifdef GLFW_INCLUDE_NONE
+#undef GLFW_INCLUDE_NONE
+#endif
 #include <GLFW/glfw3.h> // Will drag system OpenGL headers
 
 // [Win32] Our example includes a copy of glfw3.lib pre-compiled with VS2010 to maximize ease of testing and compatibility with old VS compilers.