[cairo] Fill+stroke optimisation for the SVG backend

[Adrian Johnson]

Emmanuel Pacaud wrote:
> The thing I don't like in what I've done is the new fill-stroke backend
> method, which seems redundant with the two other fill and stroke
> methods. And also I wonder if this optimisation makes sense for the PDF
> and PS backends. Is it possible to use the same path data for fill and
> stroke in a PDF or PS file ?

PDF has a fill then stroke operator so this optimisation can be done. In
PS the path can be reused by wrapping the fill in a gsave/grestore.