fixed accidental global variables created by psiturk.js
fixed accidental global variables created by psiturk.js

psiturk.js created some (I believe) unwanted global variables, like "data" and "qd". These might conflict with the user's own.

rbtrace/psiTurk,NYUCCL/psiTurk,suchow/psiTurk,pfeyz/psiTurk,pfeyz/psiTurk,mshvartsman/psiTurk,michaelpacer/psiTurk,kachergis/psiTurk,kachergis/psiTurk,NYUCCL/psiTurk,andyh616/psiTurk,pfeyz/psiTurk,mshvartsman/psiTurk,berkeley-cocosci/psiTurk,suchow/psiTurk,berkeley-cocosci/psiTurk,andyh616/psiTurk,NYUCCL/psiTurk,andyh616/psiTurk,johnmcdonnell/psiTurk,michaelpacer/psiTurk,rbtrace/psiTurk,kachergis/psiTurk,mshvartsman/psiTurk,rbtrace/psiTurk,berkeley-cocosci/psiTurk,johnmcdonnell/psiTurk,michaelpacer/psiTurk,suchow/psiTurk,johnmcdonnell/psiTurk