Refine default optimization settings
Refine default optimization settings

For baseline builds on Clang/GCC, use `-O1` but allow that to be overridden by settings for the build type (e.g. Release).

For MSVC, remove flags that actually *prevented* `SAFESIDE_ALWAYS_INLINE` from working in Debug builds.

google/safeside,google/safeside,google/safeside,google/safeside