Fix ReferenceError
Fix ReferenceError

Declare loop counter, otherwise we get an

  Uncaught ReferenceError: i is not defined at Function.arange (jstat.js:428)

PR-URL: https://github.com/jstat/jstat/pull/227
Reviewed-by: Trevor Norris <9cb5491eb5770dd8e0bf77a8a0335abf5f0488c5@gmail.com>

jstat/jstat,jstat/jstat