definitions of HYPRE_RELEASE_VERSION.
Added macros to convert HYPRE_VERSION_STRING to a string.
use that number to define the MFEM config macro MFEM_HYPRE_VERSION. In the methods HypreLOBPCG::SetRelTol and HypreAME::SetRelTol, check for suitable HYPRE version; if the version is old, generate run-time error.