ES5 set/get for numerator and denominator, to verify that they are integer values, #45
ES5 set/get for numerator and denominator, to verify that they are integer values, #45

Signed-off-by: Chris Malley <74b2712074b149d140079dbd7e875955d192e617@pixelzoom.com>

phetsims/phetcommon,phetsims/phetcommon,phetsims/phetcommon