\times vs. \tuplet

[Graham Percival]

Proposal: deprecate \times, use \tuplet instead.

Previous discussions about this went off in a discussion about scheme 
(or schemifying the entire input syntax) and whatnot, so nothing ended 
up happening.

I believe that simply replacing the command "\times" with "\tuplet" 
would be an easy change (including for convert-ly).  If we're going to 
make this change at any point in the next two years, this the ideal time 
to do it, while we're still working on GDP, LSR, and whatnot.

Thoughts?
- Graham