extend rsvg-convert to emit CairoScript data
currently rsvg-convert can emit (Cairo's) XML data, I propose to another data for debugging, CairoScript. In comparison with XML, CairoScript is replayable and possible to be rendered onto different surfaces. As XML data could be generated by 2 ways (-f xml, and -f recording), this patch provides 2 ways to emit CairoScript data (-f script, and -f recording-script), as follows.
- xml: create xml surface for first and the content is emitted during rendering.
- script: create script surface for first and (ditto).
- recording: create recording surface for first and the content is emitted as xml after rendering.
- recording-script: create recording surface for first and the content is emitted as cairo-script after rendering.