also:
- added ability to construct values from wide strings and u8 strings
- added non-template version of array::is_homogeneous()
- added explicit instantiations for more template types when `!TOML_ALL_INLINE`
- cleaned up abi namespaces
- simplified build and test machinery on windows
- removed TOML_CHAR_8_STRINGS since it no longer makes sense
also:
- fixed infinity and NaN-related code breaking when using -ffast-math and friends
- added much more detail to many static_assert error messages
- added more test permutations of various compiler flags
- added many more static checks to test code