cran-comments.md

This update is purely to update the internals of the package. It has been checked on windows, mac and linux on old, current and devel versions of R.

I've fixed compilation warnings like "use of bitwise '&' with boolean operands" on mac.

Summary of changes:

• Upgraded to a recent version of the external library CppAD.
• Moved to an install method via a configure that is more faithful to the recommended installation methods for CppAD.
• Replaced use of ellipsis with rlang