A comparison of gl/cogl-texture.c and gles/cogl-texture.c, to reduce

differences and improve maintainability.

	* clutter/cogl/gl/cogl-context.h:
	Adds a CoglTextureGLVertex typedef + texture_vertices and
	texture_vertices_size members to CoglContext for using vertex arrays
	like GLES does

	* clutter/cogl/gl/cogl-context.c:
	Initializes texture_vertices + texture_vertices_size members

	* clutter/cogl/gl/cogl-internal.h:
	Adds COGL_ENABLE_COLOR_ARRAY

	* clutter/cogl/gl/cogl.c:
	Add COGL_ENABLE_COLOR_ARRAY support to cogl_enable

	* clutter/cogl/gles/cogl-context.h:
	Change the CoglTextureGLVertex to use GLfloat for the position
	and texture coord attributes and GLubyte for the color.

	* clutter/cogl/gles/cogl-texture-private.h:
	Adds a wrap_mode member like GL has.

	* clutter/cogl/gl/cogl-texture.c
	* clutter/cogl/gles/cogl-texture.c:
	Improves the comparability of the files, such that the remaining
	differences, better reflect the fundamental differences needed
	between GL and GLES. Notably GL no longer uses glBegin/glEnd for
	submitting vertices, it uses vertex arrays like GLES and this gives
	a small but measurable fps improvement for test-text.

clutter/cogl/gl/cogl-context.c

@@ -57,6 +57,8 @@ cogl_create_context ()
   _context->path_nodes_size = 0;
   
   _context->texture_handles = NULL;
+  _context->texture_vertices_size = 0;
+  _context->texture_vertices = NULL;
   
   _context->fbo_handles = NULL;
   _context->draw_buffer = COGL_WINDOW_BUFFER;