[Cairo] Cairo API change: cairo_get_* -> cairo_current_*

[Carl Worth]

On Sep 4, Owen Taylor wrote:
 > I might suggest simply breaking stuff and letting people fix.
 > Cairo isn't mature enough yet to clutter the source code with
 > fancy ways of doing deprecation, IMHO.

I admit it's gratuitous at this point. But it was fun to experiment
and this way I hope to have something in place later when we really
want it.

I should point out that there's no permanent clutter here. All the
deprecated APIs will go away at the time of the first release, (and
the fancy macros can disappear then too). Shouldn't be much more than
"grep -iv deprecate".

-Carl