Add a studio 'say' block that accepts a time input in seconds

Goal: for playlab counting levels, sprites should be able to count 1..100 without taking minutes to complete.

<img src="https://cloud.githubusercontent.com/assets/413693/4946726/22c8d1f2-6618-11e4-8fae-17db53171357.png" width="400">

If an object is on multiple lines like this, i prefer the form:
studio.queueCmd(id, 'saySprite', {
  foo: foo,
  bar: bar,
})
(but with good indentation that I dont know how to do in markdown)