Added the WAIVER associated with the UNLICENSE

[zcdziura]

For the purposes of this explanation, instances of the word "Unlicense" shall refer to the designers of the document. "unlicense" shall refer to the actual unlicense document.

Unlicense makes the recommendation that any major contributors to a project covered by the unlicense should digitally sign a waiver. They even go so far as to provide a simple template waiver paragraph, which should be included as its own standalone file.

I have added that particular file.