[TIMOB-5880] iOS - Expose "error" event in remote images

Feature Request:

Expose "error" event in imageViews

Description

If a remote image fails to render, the console outputs the following:

[ERROR] Failed to load image:'http://someimage.png', error: .... 

We need a way to catch that error in the Javascript so that we can act accordingly, for example, show an "error_image.png".

Example:

var img = Ti.UI.createImageView({
	image:'http://someurl.com/someimage.png'
});
win.add(img);
img.addEventListener('error', function(){
	img.image = 'error_image.png';
});