Fixed minor bugfixes with dimensions being improperly
set in vtkUniformGrid & vtkAMRBox. Re-implemented the
vtkHierarchicalBoxDataSet::GenerateVisibilityArrays()
method. Albeit slower, it is working with Enzo data well.
Added functionality in vtkAMRBox to compute physical
coordinates of a given point based on the corresponding
i-j-k computational coordinates & extended vtkSerializable
to provide support for object serialization and deserialization.