Changed the xcairo driver so that it can be configured to use an external X Drawable using a patch provided by Jonathan Woite. This allows one to use PLplot to draw graphs in pre-existing X windows which PLplot neither owns nor manages.
Changed the xcairo driver so that it can be configured to use an external X Drawable using a patch provided by Jonathan Woite. This allows one to use PLplot to draw graphs in pre-existing X windows which PLplot neither owns nor manages.

svn path=/trunk/; revision=8258

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