check if we need to explicitly link with a libiconv library
Update Cogl description in README.in
update cogl.doap
Remove some leftover references to Clutter

Since it's not possible to build Clutter against Cogl master it doesn't
make sense to have any Clutter specific code.
sdl2: fix GL driver selection
Enable building without gtk-doc, e.g. on OSX
stash: cogl-gst: cogl_gst_video_sink_get_natural_size()