Examples: OpenGL3: Remove misleading or unnecessary "#version 150" strings.

examples/imgui_impl_opengl3.cpp

@@ -31,7 +31,7 @@
 //#include <glew.h>
 
 // OpenGL Data
-static char         g_GlslVersion[32] = "#version 150";
+static char         g_GlslVersion[32] = "";
 static GLuint       g_FontTexture = 0;
 static int          g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0;
 static int          g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0;

examples/imgui_impl_opengl3.h

@@ -9,7 +9,7 @@
 // The 'glsl_version' initialization parameter defaults to "#version 150" if NULL.
 // Only override if your GL version doesn't handle this GLSL version. Keep NULL if unsure!
 
-IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_Init(const char* glsl_version = "#version 150");
+IMGUI_IMPL_API bool     ImGui_ImplOpenGL3_Init(const char* glsl_version = NULL);
 IMGUI_IMPL_API void     ImGui_ImplOpenGL3_Shutdown();
 IMGUI_IMPL_API void     ImGui_ImplOpenGL3_NewFrame();
 IMGUI_IMPL_API void     ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data);