feat(android): expose ImageOverlay image setter

[m1ga]

Exposes the image setter of an ImageOverlay and you can use external URLs now:

var Map = require('ti.map');
var win = Titanium.UI.createWindow();

var mapview = Map.createView({
	mapType: Map.NORMAL_TYPE,
	region: {
		latitude: 34.4311,
		longitude: -118.6012,
		latitudeDelta: 0.01,
		longitudeDelta: 0.01
	},
	animate: true,
	regionFit: true,
	userLocation: true,
});

let imgOverlay = Map.createImageOverlay({
	image: "https://picsum.photos/200/200",
	boundsCoordinate: {
		topLeft: {
			latitude: 34.4311,
			longitude: -118.6012
		},
		bottomRight: {
			latitude: 34.4194,
			longitude: -118.5912
		},
	},
})
mapview.addImageOverlays([imgOverlay]);
setTimeout(function() {
	imgOverlay.image = "/image2.png";
}, 2000);
win.add(mapview);
win.open();

• add image: image2.png
• extern URL will be shown
• image2 will be shown after 2 seconds

ti.map-android-5.6.2.zip

Merge #678 first for workflow and map update