message: GLRenderer: adds missing copyright-header
diff: +/**
  + * This file is part of the "libterminal" project
  + * Copyright (c) 2019 Christian Parpart <christian@parpart.family>
  + *
  + * Licensed under the Apache License, Version 2.0 (the "License");
  + * you may not use this file except in compliance with the License.
  + *
  + * Unless required by applicable law or agreed to in writing, software
  + * distributed under the License is distributed on an "AS IS" BASIS,
  + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  + * See the License for the specific language governing permissions and
  + * limitations under the License.
  + */
  #pragma once
  #include <terminal/Logger.h>
  