Support for itunes:order and itunes:isClosedCaptioned

As defined in http://www.apple.com/itunes/podcasts/specs.html#isClosedCaptioned
Enum values should be in uppercase. Please change this to something like 
```
public enum YesNo {

	YES("yes"),
	NO("no");
	
	private String stringValue;
	
	private YesNo(String stringValue) {
		this.stringValue = stringValue;
	}
	
	public YesNo getByStringValue(String stringValue) {
		for (YesNo yesNo : values()) {
			if(yesNo.stringValue.equals(stringValue)) {
				return yesNo;
			}
		}
		return null;
	}
	
}
```