Added OpenGL debug groups for most graphics operations when love is built in debug mode for iOS. The Xcode frame capture tool uses them to create nice visual groups for OpenGL function calls.

src/modules/graphics/opengl/Shader.cpp

@@ -210,6 +210,8 @@ void Shader::mapActiveUniforms()
 
 bool Shader::loadVolatile()
 {
+	OpenGL::TempDebugGroup debuggroup("Shader load");
+
     // Recreating the shader program will invalidate uniforms that rely on these.
     lastCanvas = (Canvas *) -1;
     lastViewport = OpenGL::Viewport();