Panels for-in javascript iterators lead to incomplete experience when the array prototype is extended.

Having just had an issue where additional javascript extended the Array prototype, it was noticable that IPE stopped functioning accross pages.

At the point of attaching behaviour, there is a for loop done in Javascript, however prototype additions are included in this loop leaving a Drupal thrown JS execution and an incomplete attachment of the IPE.

As such, changing the for from a for-in iterator to a tradition for across the javascript array makes sense and prevents the inclusion of any prototype additions and interface javascript errors.