added check for object to save the url

checks the values to see if it is an image object, and if it is, it will display the url for the image file.

papaparse.js

@@ -362,6 +362,14 @@
 			if (typeof str === 'undefined' || str === null)
 				return '';
 				
+			
+			// if the String passed in that we are checking in the unparse
+			// is a object (which means it is a img file from the json)
+			// so get the url from it, so users can access the file.
+			if(typeof str ==="object") {
+				return str.url;
+			}
+
 			str = str.toString().replace(/"/g, '""');
 
 			var needsQuotes = (typeof _quotes === 'boolean' && _quotes)