zoomTo - Rendered in the constructor

[belug]

With one of te last updates of the zoomTo widget the render was forced in the the createWindow that was called in the constructor.

With super long to init apps like ours, the render could be called before the dom is ready.

[belug]

fix for the render in constructor

[belug]

Here's a fix that remove the render from the constructor and add it to the recenter.

And I changed the show/hide technique to use the render method insted.

[adube]

This fix was made in trunk past 1.2 and is applied to a lib.

[adube]

The issues was introduced in #418, so I'm tagging this fix to it.

[adube]

Fixed in r1139.

[adube]

The correct revision is : r1339, sorry.