Re: fisrt version of physical constants module + codata

Use whatever licence you are normally using for my stuff. Don't know
about Chucks version.

NIST website: "These World Wide Web pages are provided as a public
service by the National Institute of Standards and Technology (NIST).
With the exception of material marked as copyrighted, information
presented on these pages is considered public information and may be
distributed or copied. Use of appropriate byline/photo/image credits
is requested.", so that should be ok.

Bas