same zoom speed as our previous polymaps version

[sttawm]

This slows down mouse-wheel scrolling by 5x.

I wonder if we're messing up the safari experience, though. There's a comment in Wheel.js:

  // mousewheel events are totally broken!
  // https://bugs.webkit.org/show_bug.cgi?id=40441
  // not only that, but Chrome and Safari differ in re. to acceleration!

(btw the above bug relates to the speed of mousewheel deltas and is marked as resolved)

Can someone with a mac make a recommendation here?

[mpruett]

Enhance.