Fix for when the window resizes and iScroll's parents are display:none. 

Fix for bug where iScroll can get very confused if the window changes size while one of the parents of the div with iScroll on it is hidden by display:none. This causes the widths and heights within iScroll to be zero and iScroll miscalculates the sizes of stuff. This can happen very often within PhoneGap on Android as both the childBrowser pluggin and even an alert box can trigger a window resize event. So any iScrolls hidden by many of the mobile JavaScript libraries will not work. 

Ideally when a page with an iScroll on it becomes visible again then iScroll.refresh() should be called. But I haven't yet figured out an automated way to do this.