Deprecate ClutterShader

With the instantiatable ClutterShaderEffect, the only reason for
ClutterShader to exist is to make the ClutterActor::paint implementation
miserable.

Yes, ClutterShader doesn't use a FBO, so it's "more efficient" on
ClutterTextures. It's also generally wrong unless you know *exactly* how
the actor's pipeline is set up — something we cannot even guarantee
internally unless we start doing lame type checks.

clutter/clutter-shader-types.h

@@ -29,7 +29,6 @@
 #define __CLUTTER_SHADER_TYPES_H__
 
 #include <glib-object.h>
-#include <cogl/cogl.h>
 
 G_BEGIN_DECLS