[Cairo] Cairo on Windows

[Carl Worth]

On Sep 4, Maarten Breddels wrote:
 > The Cairo API is way better then Ghostscipt, which makes it easier
 > to work with, and faster.

Thanks for the encouragement.

 > Sure, I'll clean it up, and write some docs, hopefully I have some time
 > tomorrow.

OK, I'll look forward to that.

 > I also found out it crashes when I don't set the color, and call stroke.

What do you know --- I just committed a fix for that. It also fixes
the crashes when calling set_rgb_color, stroke, or fill before calling
one of the set_target_functions.

-Carl