Handle ZXingError class in iOS wrapper (zxing-cpp#877)

ios: Handle all errors by catching exceptions of any type (save guard against crash)

Author: GUIEEN

wrappers/ios/Sources/Wrapper/Reader/ZXIBarcodeReader.mm

@@ -146,6 +146,9 @@ - (instancetype)initWithOptions:(ZXIReaderOptions*)options{
     } catch(std::exception &e) {
         SetNSError(error, ZXIReaderError, e.what());
         return nil;
+    } catch (...) {
+        SetNSError(error, ZXIReaderError, "An unknown error occurred");
+        return nil;
     }
 }