[docs] Ignore I420.h and YV12.h
[docs] Ignore I420.h and YV12.h

Those files are autogenerated and the ARBfp1.0 shaders are defined
there. These file should really not be parsed by gtk-doc.

ystreet/clutter-gst,lubosz/clutter-gst,GNOME/clutter-gst,ystreet/clutter-gst,ystreet/clutter-gst,GNOME/clutter-gst,GNOME/clutter-gst,GNOME/clutter-gst,skinkie/clutter-gst,lubosz/clutter-gst,skinkie/clutter-gst,lubosz/clutter-gst,ystreet/clutter-gst,skinkie/clutter-gst