Fix pinchzoom example disappearing in IE

In IE 10/11, setting an element's transform with a scale3d where the
z-axis's scale is 0 will effectively hide the element. This means that
as soon as the picture was touched, the picture would disappear.

Fix was tested in IE 11 and Chrome 32.0.1700.107.
Merge pull request #471 from mgbennett/master

Fix pinchzoom example disappearing in IE