[cairo] cairo_current_xxx, reference or not?

[David Reveman]

With the recent font changes, cairo_current_font returns a cairo_font_t
object that needs to be destroyed. This is different from before and
different from what cairo_current_pattern and
cairo_current_target_surface are doing. If this is the intended
behavior, cairo_current_pattern and cairo_current_target_surface should
probably be modified to return a references instead of just pointers.
It's a bit confusing right now.
 
-David