fix XCode config, add icons

app/ios/Examples/Example_SPM/NFCPassportReaderApp/Extensions/StringExt.swift

@@ -0,0 +1,40 @@
+//
+//  StringExt.swift
+//  NFCPassportReaderApp
+//
+//  Created by Andy Qua on 30/06/2019.
+//  Copyright © 2019 Andy Qua. All rights reserved.
+//
+
+import Foundation
+
+/// Some Utility methods for string -  access characters by index
+extension String {
+    subscript(_ i: Int) -> String {
+        let idx1 = index(startIndex, offsetBy: i)
+        let idx2 = index(idx1, offsetBy: 1)
+        return String(self[idx1..<idx2])
+    }
+    
+    subscript (bounds: CountableRange<Int>) -> String {
+        let start = index(startIndex, offsetBy: bounds.lowerBound)
+        let end = index(startIndex, offsetBy: bounds.upperBound)
+        return String(self[start..<end])
+    }
+    
+    subscript (bounds: CountableClosedRange<Int>) -> String {
+        let start = index(startIndex, offsetBy: bounds.lowerBound)
+        let end = index(startIndex, offsetBy: bounds.upperBound)
+        return String(self[start...end])
+    }
+    
+    subscript (bounds: CountablePartialRangeFrom<Int>) -> String {
+        let start = index(startIndex, offsetBy: bounds.lowerBound)
+        return String(self[start...])
+    }
+    
+    func strip() -> String {
+        let trimmed = self.trimmingCharacters(in: .whitespacesAndNewlines)
+        return trimmed
+    }
+}