ENH: Add XdmfGridRegular for CoRectilinear (Regular) Structured Grids.  Add test for interaction and output.

The macros
XDMF_CHILDREN and XDMF_CHILDREN_IMPLEMENTATION

add capabilities to add and remove children by index or property from a parent item.  This simplifies the code
as the same insert() getChild() calls were used throughout the code.

Added macro CLEAN_(language)_TEST() which takes in the executable
name and a list of output files that need to be removed during
'make clean.'

At the top level, this allows you to build just the core or build
everything. If you choose to build just the core you are still able
to wrap it with Java or Python, build testing or the documentation.

Tests that are within core, are now labled as such:
	(language)Core_(TestName)
Also updated format for Java and Python Test Output

The testing suite should make it easier to add new tests. It also
makes use of a single .cmake.in file that gets reconfigured for
each test, instead of creating a new .cmake.in file for each test.
Look into the core/CMake/Use*.cmake files to see how to add new tests.

Within SWIGJAVA, there were a few duplicate ignores and and endif
that I removed.

Since we are creating jars in the top directory, we can just look
there and use '*' to grab them all for our classpath.

This commit moves both Java and Python add_package to the Top Level.
It also contains macros to swig Java and Python. This is because
we end up doing the same thing inside core and outside core for both.

Ken sent me a manual patch, which I applied to grab the Java Changes.

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: Revert back to XdmfGridCollection inheriting from XdmfGrid - we want the flexibility to be able to add global sets (might be necessary for dft work).

ENH: Begin adding install rules.  Modify bug in XdmfWriter that resulted in XdmfArrays not being written in certain cases.

ENH: Remove XdmfGrid inheritance from XdmfGridCollection.  If there is a need for Sets/Attributes at the "global" collection level then we can deal with it in the future.

ENH: Commit Ken Renard's patches modifying populateItem and XdmfCoreReader to support some xpath functionality for backwards compatibility.

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: Make XdmfSet behave like a real std::set.  Modify some writing functionality to make this possible.

ENH: Make XdmfGridCollection inherit from XdmfGrid and XdmfDomain, since it is really a unity of the two classes.  Modify some details in ItemFactory / Reader.