Not working in prod with webpack
Hi,

I get a weird issue.

Everything works fine in dev mode.
But when I push my minified code to production I get this :

`Minified exception occurred; use the non-minified dev environment for the full error message and additional helpful warnings.`

Also my color picker is empty and when I try to click on the color picker I get this : `Uncaught TypeError: Cannot read property 'clientWidth' of undefined`

![capture d ecran 2016-04-28 a 10 28 23](https://cloud.githubusercontent.com/assets/5103928/14879861/f6288d92-0d2b-11e6-80a1-6dd9e24dd039.png)

Any idea ? 

Thanks for this great plugin !
