dae <scene> transforms are not parsed properly

[jbohren]

If a mesh has a visual_scene/node/matrix that is not identity, it isn't parsed properly by RenderableMesh

--- a/meshes/arm_segment_b.dae Wed Aug 22 14:30:12 2012 +0200
+++ b/meshes/arm_segment_b.dae Thu Aug 23 10:54:52 2012 +0200
@@ -136,8 +136,8 @@
<visual_scene id="Scene" name="Scene">

•               -0.0 -1.0 0.0 0.0 
  

•               1.0 -0.0 0.0 0.0 
  

•               1.0 0.0 0.0 0.0 
  

•               0.0 1.0 0.0 0.0 
              0.0 0.0 1.0 0.0 
              0.0 0.0 0.0 1.0 
          </matrix>