licenses.texi and sectioning commands

[Karl Berry]

rms suggested simply removing the @node and any sectioning command
at all from the beginning of the Texinfo versions of the licenses.  That
way manuals can do whatever they want.

Sounded sensible to me, so barring objections, I'll make those changes
in a bit.

It will require some changes in existing licenses, but then, doing
anything to resolve the current inconsistent situation will do that.

karl