ENH: Define GenericIODefinitions

Move global data-structures and variables in
GenericIODefinitions.hpp
ENH: SwapHeader utility functions

Added functions to GenericIOUtilities to swap
the endian of Global,Variable and Rank headers.
ENH: Move common functionality to GenericIOReader

Moved common functionality and data-structures to
all readers in GenericIOReader.
ENH: Simple driver to test GenericIOReader

Implemented a simple driver code to help guide the
development of the GenericIOReader.
COMP: Copy also *.hpp files to /include
WIP: GenericIO MPI reader