* fixed noexept warnings
- Removed conditional compilation for throwing version of GSL
vs fail_fast because we don't want users of the code to see
differences in the span interface dependent on error mechanism
chosen
- Removed noexcept from functions that may fail at runtime
- Fixed CppCoreCheck warnings related to missing and incorrect
noexcept
- do not warn on unnown attributes for GCC and Clang
* remove suppress that does not compiler for clang and gcc