Rework of HeavyDataController and HDF5Controller to remove extra code and move HeavyDataController away from being too dependent on hdf5 style
XdmfFunction now supports negative numbers in addition to the - operator
Reworked the interaction between array references and reading
Cleaned up some warnings that showed up in pedantic
Adjusted mpi tests to test against the MPIEXEC variable as opposed to hard calling mpirun
Still needs to be changed to work better with Cray mpi style execution
Updates to XdmfArrayType to allow for signed and floating point checking
General test and Documentation updates