[Rd] Suggestion: Add box constraints to optim() default Nelder-Mead

[ivo welch]

Title says it all.

I know this can be done by transformations by the user, but given that
interval is so prominent in the ?doc and given that Nelder-Mead is the
default method for optim(), it would be nice if the default method would
honor this one, too.

[could be done (even by me) within the R code because the C code through
the arctan transforms]

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