+ provide access to 'root' collision shape, in case the original collision shape is temporarily replaced by a child collision shape.

+ added MultiMaterialDemo showing how to use the new btTriangleIndexVertexMaterialArray.
Thanks to Alex Silverman for this contribution!

Demos/MultiMaterialDemo/main.cpp

@@ -0,0 +1,22 @@
+
+#include "MultiMaterialDemo.h"
+#include "GlutStuff.h"
+
+#include "GlutStuff.h"
+#include "GLDebugDrawer.h"
+#include "btBulletDynamicsCommon.h"
+
+GLDebugDrawer	gDebugDrawer;
+
+int main(int argc,char** argv)
+{
+
+        MultiMaterialDemo* multiMaterialDemo = new MultiMaterialDemo();
+        multiMaterialDemo->initPhysics();
+        multiMaterialDemo->setCameraDistance(30.f);
+        
+        multiMaterialDemo->getDynamicsWorld()->setDebugDrawer(&gDebugDrawer);
+
+        return glutmain(argc, argv,640,480,"Multimaterial Mesh Demo",multiMaterialDemo);
+}
+