Using statements have been added to XdmfSharedPtr.hpp. All used of
boost::shared_ptr and boost::shared_dynamic_cast have been replaced
by shared_ptr and shared_dynamic_cast. Slight modification to XdmfCore.i
to get swig wrapping working again.
Hopefully this will become a standard style for Xdmf development.
All spaces - 80 character line wrapping.
ENH: Rename all subclasses of XdmfGrid to more syntactically friendly names: i.e. XdmfGridUnstructured to XdmfUnstructuredGrid.