Supports chrome browser (v11) on google tv

add setter to avoid exception [1] and using defineProperty instead of __defineGetter__ to inheritance error [2]

[1]: TypeError: Cannot set property interationTIme of par 0-NaN(0@0) [par 1-undefined (0 @-0.994)[] ] which has only a getter
[2]: can't found super object (ParGroup) if it's using __defineGetter__