license & copyright patch to MELT for dual GPLv3+ & GFDL1.2+

[Richard Kenner]

> My bad understanding of the paragraph above makes me believe that some
> FSF people (RMS?) are suggesting that a license applies to small chunks
> of a file, so that some file could have some of its lines licensed under
> GPL and other lines licensed under LGPL. I believe that my understanding
> is incorrect.

My reading is exactly the opposite: that because a file can have only
ONE license, the only way it could possibly be dual-licenced is if
EVERYTHING in the file was licensed in that way.