Please explicitely state licensing terms until merged into Boost

[fawick]

As far as I am able to understand, the goal is to have this code included by the Boost project, ultimately making the Boost License become applicable for it. The goal of this issue is to provide legal certainty for fetching and using this code in its current form directly from here.

@artyom-beilis Until the inclusions happens, would you kindly consider adding an explicit license statement to clarify how you license your work to the public (e.g. by declaring the Boost License relevant and applicable even now or releasing the code in its current form into the public domain).

I saw that a fork of this project already added a LICENSE, but since this license statement was not given by @artyom-beilis I doubt it can be considered binding webmaster128@19e7a4c

EDIT: grammar

[artyom-beilis]

Thanks for reminder. I added the license