Made the more of the OSG's referenced object desctructors protected to ensure

that they arn't created on the stack inappropriately.

Split the implemention of Matrix up so that it is a simple no referenced counted
class and can be safefly created on the stack.  To support referenced counting a
seperate subclass now exists, this is RefMatrix which inherits from both Matrix and
Object.

src/osg/MatrixTransform.cpp

@@ -5,14 +5,12 @@ using namespace osg;
 MatrixTransform::MatrixTransform():
     _inverseDirty(false)
 {
-    _matrix = new Matrix;
-    _inverse = new Matrix;
 }
 
 MatrixTransform::MatrixTransform(const MatrixTransform& transform,const CopyOp& copyop):
     Transform(transform,copyop),
-    _matrix(new Matrix(*transform._matrix)),
-    _inverse(new Matrix(*transform._inverse)),
+    _matrix(transform._matrix),
+    _inverse(transform._inverse),
     _inverseDirty(transform._inverseDirty)
 {    
 }
@@ -21,8 +19,7 @@ MatrixTransform::MatrixTransform(const Matrix& mat )
 {
     _referenceFrame = RELATIVE_TO_PARENTS;
 
-    _matrix = new Matrix(mat);
-    _inverse = new Matrix();
+    _matrix = mat;
     _inverseDirty = false;
 }
 
@@ -35,11 +32,11 @@ bool MatrixTransform::computeLocalToWorldMatrix(Matrix& matrix,NodeVisitor*) con
 {
     if (_referenceFrame==RELATIVE_TO_PARENTS)
     {
-        matrix.preMult(*_matrix);
+        matrix.preMult(_matrix);
     }
     else // absolute
     {
-        matrix = *_matrix;
+        matrix = _matrix;
     }
     return true;
 }