* Support compile-time format string checking with std::format
* Fix pre-VS 17.5 compilation
* Fix compilation without wchar_t support
* What am I doing
* Bring back fmt optimization
* Move to_string_view to common.h
* Fix SPDLOG_CONSTEXPR_FUNC emitting duplicate symbol errors when building in C++11
* Also add inline on VS 2013
* Appender doesn't work on wide strings