Javadoc of BarcodeManager.isInitialized() does not match method signature

The signature of BarcodeManager.isInitialized() is
```
public boolean isInitialized()
```
yet its Javadoc talks about an int return value instead of a boolean
```
  @return <code>int</code> {@link DecodeException#SUCCESS} in case of success,
  otherwise a possible error code, matching one of the {@link DecodeException} error constants.
```