Fix for textareas that start off with no width

[pamelafox]

My textarea starts off with no width (as its hidden), so I changed the width of the shadow div to be done inside the update function:
shadow.width($this.width());

It seems to perform alright, but I don't have any performance measurements or such.

Oh, and I made it work with Zepto with simply:
}(window.jQuery || window.Zepto));

Thanks for such a Zepto-compatible lib!

[pamelafox]

Actually after testing on Android, I rewrote it quite a bit:
https://gist.github.com/2156602

It better handles textareas that start off hidden, and it has an option for not resizing in reaction to events (as Android couldn't handle the resizing, it messed up its repainting of fixed DIVs, that retarded browser). Also, now I can call it whenever I want it to resize, like when I know my textarea is being shown or when I'm filling it with new data.