[TIMOB-17328] Android: Add support for file property to HTTPClient

   function createButton(title, filename, url) {
   	var b = Ti.UI.createButton({
   		title : title
   	});
   
   	b.addEventListener("click", function() {
   		var xhr = Titanium.Network.createHTTPClient();
   		if (filename != null) {
   			xhr.file = filename;
   		}
   		xhr.onload = function() {
   			var responseFilePath = this.responseData.nativePath;
   			alert("responseData.nativePath = " + responseFilePath);
   			if (responseFilePath != null) {
   				imageView.image = responseFilePath;
   			} else {
   				imageView.image = this.responseData;
   			}
   		};
   		xhr.open('GET', url);
   		xhr.send();
   	});
   	
   	return b;
   }
   
   
   var win = Titanium.UI.createWindow({
   	title: "The 'file' property for HTTPClient",
   	layout: "vertical"
   });
   
   var imageView = Titanium.UI.createImageView({
   	top : 5,
   	height : 200,
   	width : 300
   });
   
   win.add(createButton("Not setting 'file' (download a small image)", null, "http://developer.appcelerator.com/blog/wp-content/themes/newapp/images/appcelerator_avatar.png?s=48"));
   win.add(createButton("Not setting 'file' (download a large image)", null, "http://2.bp.blogspot.com/-z-cZ7JirojQ/Tc8OMAAqbLI/AAAAAAAAAfc/slhGE764cyY/s1600/Cars+2.jpg"));
   win.add(createButton("'file' is in tempDirectory", Ti.Filesystem.tempDirectory + "/sky.jpg", "http://www.forestwander.com/wp-content/original/2009_01/Sky-View.JPG"));
   win.add(createButton("'file' is in applicationDataDirectory", Ti.Filesystem.applicationDataDirectory + "/flower.jpg", "http://flowerdeliverygo.com/wp-content/uploads/2014/05/flower-delivery.jpg"));
   win.add(createButton("'file' is in externalStorageDirectory", Ti.Filesystem.externalStorageDirectory + "/fruit.jpg", "http://southernbite.com/wp-content/uploads/2012/05/SouthernBiteFruitSalad-2.jpg"));
   
   win.add(imageView);
   
   win.open();