Add an alpha argument to setAll()

[sidewayss]

setAll() does not currently set alpha. It would be a tiny change to the code, an optional additional argument, and (barring a need for validation against invalid/undefined values) one additional line of code:
color.alpha = alpha;

[LeaVerou]

I think that makes sense. setAll() should conceptually be able to set everything that set() can, and set() can set alpha. What do others think?