[cairo] Possible minor bug in Cairomm (or Cairo) handling of surface patterns

[Asko Kauppi]

I had a situation where placing a Cairo::SurfacePattern onto SVG  
output would create results, and placing the same onto ImageSurface  
(PNG output) would not.

The reason was I didn't do:

    pat->set_extend( Cairo::EXTEND_REPEAT );

Now, all is fine and the outputs are identical. However, wasn't the  
earlier SVG output actually wrong. Cairo docs say:

	"The default extend mode is CAIRO_EXTEND_NONE for surface patterns"

	http://www.cairographics.org/manual/cairo-pattern.html

System info:

	OS:			Linux x64 (CentOS release 5.2 Final)
	Cairomm:	1.2.4
	Cairo:		1.2.4

- Asko Kauppi