* Removing pragma for 4100 (to see what is still broken with the latest code).
* Adding --keep-going
* Revert "Adding --keep-going"
This reverts commit 1c844c6ffd07a6111b644811e7e3b0a50b9d44bb.
* Introducing PYBIND11_WORKAROUND_INCORRECT_MSVC_C4100.
* _MSC_VER <= 1916
* Replacing simple variadic function with variadic template (attempt to resolve MSVC 2017 failures).
* Preserving existing comment (moved from pybind11.h to detail/common.h).
* Adding blank lines for readability.