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

[Carl Worth]

On Sep 4, Carl Worth wrote:
 > 1) I lifted some of Richard's work on the slim macros to provide
 >    aliases so the deprecated function names will work, but with useful
 >    compile-time warnings. 

Keith pointed out that my magic DEPRECATED macro preserved
source-level compatibility but broke previously compiled code still
expecting the old symbols. I've now fixed it so that the original
deprecated symbols will still be available.

-Carl