[#1732] building with -O3 and -Werror
Revert "[#1848] turn off -Werror for beta, will re-enable ASAP"

This reverts commit 83627ccf2ca2631ecd4f0b70c77d78013c69e520.
[#858] we use the master branch now
[#1732] Fixed a warning cropping up wth -O3 in CI
[#1732] Fixed a warning cropping up wth -O3 in CI, nearly identical to the last one
[#1732] Fixed another warning cropping up wth -O3 in CI
[#1892] added conditional input to packing instructions for dataObjInfo_t and collInfo_t
[#1732] remove hard error for system calls - this broke icat testing
[#1848] update release notes and release date for 4.0.0b1