specification of []int(string) and []byte(string). also clarify other string conversions.
specification of []int(string) and []byte(string).
also clarify other string conversions.

R=rsc, iant, gri, ken2
CC=golang-dev
http://codereview.appspot.com/207103
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go