easy nsuserdefaults

extension NSUserDefaults {
    @nonobjc subscript(key: String) -> AnyObject? {
        get {
            return objectForKey(key)
        }
        
        set {
            setObject(newValue, forKey: key)
        }
    }
    
    @nonobjc subscript(key: String) -> Bool {
        get {
            return boolForKey(key)
        }
        
        set {
            setBool(newValue, forKey: key)
        }
    }
    
    // etc.
}