add TODOs for loadGLMesh error handling

src/shader.cpp

@@ -252,6 +252,8 @@ loadGLMesh(const mesh& m,
 		m.indices,
 		glm.usage);
 
+	// TODO: many of these GL functions can set an error state
+	// TODO: return error status
 	glBindVertexArray(0);
 
 	return glm;