Log Message:
Update goocanvas to 1.0.0.

GooCanvas 1.0.0	(Jan 10 2011)
===============

 o Added "alpha" property to GooCanvasImage to set opacity.
 o Allow setting clip path to NULL to reset it.
 o Allow setting line dash to NULL to reset it.
 o Handle RTL direction better in GooCanvasTable.
 o Fixed GooCanvasGroup bug - use the correct scale argument in paint.
 o Fixed GooCanvasPolyline bug - update arrows when line width changes.
 o Fixed static items bug - don't clip incorrectly.
 o Improved performance a bit when creating lots of items.