"single randoms" naming consistency

[tabatkins]

Ignoring random(), which is named to be consistent with Math.random(), the other operations are numberBetween(), intBetween(), and boolean().

Do we need the "Between" parts? They're already conditioned on the Random namespace; I think having all of them more consistent with boolean() would be fine: Random.number(a, b), Random.integer(a, b), and Random.boolean()

[bakkot]

I vote for dropping the between.