Make it ie8 compatible (sort of).

In modern js engine a array like [1,2,3,] will be intepreted as [1,2,3] 

But under IE8 it turned to [1,2,3,undefined]

I fix some little issue related with it. After this fix it's able to run under IE8 with some(many) other pollyfill. But those pollyfill can be done out side the swig.