* Initial updates for HDF5 1.8.23 release
Update so numbers for release
Set version to 1.8.23
Switch default build mode to production for release in configure.ac
Set HDF5_GENERATE_HEADERS to OFF in src/CMakeLists.txt
Commit Makefile.ins and other generated files for release
except ...~ files and autom4te.cache.
* Update platforms tested.