New enum PrimitiveParams, with the resolved parameters for each filter primitive
New enum PrimitiveParams, with the resolved parameters for each filter primitive

We will resolve all the parameters that each primitive needs, and put
them in this enum.  Upcoming changes:

* Each primitive will be able to extract a PrimitiveParams for itself.

* Static dispatch for rendering primitives, based on this enum.

* Later, synthesize PrimitiveParams not from feFoo elements, but from
filter functions in the SVG2 `filter` property.

GNOME/librsvg,GNOME/librsvg,GNOME/librsvg,GNOME/librsvg