Re-organize the source layout

As part of an effort towards being able to write non-opengl based
backends for Cogl this moves most of the opengl specific code under
drivers/gl. drivers/gl and drivers/gles have been moved to
drivers/gl/gl and drivers/gl/es respectively.

Reviewed-by: Neil Roberts <neil@linux.intel.com>

(cherry picked from commit 7dc482facb0a265c7f48660079e7e12dd7a2813e)

cogl/driver/gl/cogl-pipeline-progend-fixed-private.h

@@ -0,0 +1,36 @@
+/*
+ * Cogl
+ *
+ * An object oriented GL/GLES Abstraction/Utility Layer
+ *
+ * Copyright (C) 2011 Intel Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ *
+ *
+ * Authors:
+ *   Neil Roberts <neil@linux.intel.com>
+ */
+
+#ifndef __COGL_PIPELINE_PROGEND_FIXED_PRIVATE_H
+#define __COGL_PIPELINE_PROGEND_FIXED_PRIVATE_H
+
+#include "cogl-pipeline-private.h"
+
+extern const CoglPipelineProgend _cogl_pipeline_fixed_progend;
+
+#endif /* __COGL_PIPELINE_PROGEND_FIXED_PRIVATE_H */
+