Revise copyright license grant language to use statutory language.

See: https://github.com/richardfontana/copyleft-next/issues/24

Issue noted by @pchestek:

    In the grant, my practice is to use the statutory language
    (admittedly U.S.) of the exclusive rights of the author so it's
    unassailably clear which rights you are licensing. If you don't
    like that, I would be ok with “copy” instead of "reproduce"
    (although there are statements in case law that “copy” is
    shorthand for “infringe any of the exclusive rights of the
    author,” so using the word “copy” leaves room for a little bit of
    mischief) but I have no idea what “make” might mean in a copyright
    context. (I think compiling the source code would be preparing
    derivative work, so that wouldn't be “making” a work.) You also
    should specifically grant the right to prepare derivative works –
    it's clearly intended and implied, but a little odd not to
    expressly state it when it's probably the most important right
    you're granted. I debated whether to say “prepare Derived Works”
    or “prepare derivative works” and decided the latter was right
    because then there couldn't be any ambiguity about whether there
    was some type of derivative work that the license didn't allow you
    to create, i.e., one that would be a derivative work but that
    wouldn't be a Derived Work. For the same reason I lower-cased
    “Distribute,” to make it clear that you were granting a license
    for all distribution rights, not just ones you define.

    You might want to consider looking at foreign law to see whether
    there are any other concepts you should include in the grant.