Use rut-graph _init_type() style elsewhere

**On Wed, May 29, 2013 at 06:41:08PM +0100, Bragg, Robert wrote:**
````
> One thing to note when looking at existing components is that none of them
> currently follow the rut-type style that I referred you to in rut-graph so
> if you see the _init_type() function then the vtables may be scattered
> within the C file and we used to have to make lots of manual changes based
> on the name of the type. If you add a new component it would be good if you
> can follow the style in rut-graph.c. If you fancy making a separate patches
> to update any of the other components to follow the newer style too that
> could also be cool :-)
````

Thought I'd make a start on this to make sure I'm on the right tracks