Added Psiturk to project (*mainly* for testing)

PsiTurk code does not work yet combined with my code.

GOAL: .py script produces a function that uses PsiTurk for display and
response storage, which is called by task.js; some *magical* (= I don’t
know what should go in it) HTML code is generated for stage.html, by
the PsiTurk convention.

Current state: Started writing new function, JSgenForPsiTurk(), that
would output the Experiment() JavaScript function. Main difference
between JSgen() and JSgenForPsiTurk() — the latter uses jQuery, and
follows the structure of StroopExperiment() in the PsiTurk example’s
task.js. There are place marks for different functionality of
JSgenForPsiTurk().