Modify XdmfTopologyConverter and XdmfPartitioner to work with new
topology types.

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boost::shared_ptr and boost::shared_dynamic_cast have been replaced
by shared_ptr and shared_dynamic_cast.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.

ENH: Added XdmfGridUnstructured and turned XdmfGrid into an abstract base class for all grids (both structured and unstructured).  Modified a bunch of utils and other classes
to fit this new hierarchy.

ENH: Change some method names in XdmfArray to be clearer and less verbose.  Modify files for documentation clarity.  Modify some minor things to prevent -Wall warnings in gcc.  Add python install rules and rpathing.

ENH: Modify several utils to take XdmfHDF5Controller as an argument so that they can write data to hdf5 as generated rather than keeping it all in memory.  This is an optional argument.

ENH: Add XdmfExodusReader for reading ExodusII files into Xdmf.  Add ability for XdmfArray::initialize() to take a size value to initialize the array to.

ENH: Rethink XdmfWriter / XdmfCoreWriter distinction and move XdmfSet to XdmfArray conversion in XdmfSet's traverse method.  If conversion is unneeded then do not traverse XdmfSet.

ENH: Rename get/set ItemProperties for conciseness.  e.g. getAttributeCenter ---> getCenter .  This follows
what is done for XdmfArray (getType).

ENH: Add python wrapping for XdmfUtils and modify some swigisms to get reader working properly in python.

ENH: Begin implementing XdmfTopologyConverter.  Fix typo in XdmfArray that incorrectly initialized UInt32() type.