Update to Duktape 1.0.2

Hey @judofyr, I don't know if you're still maintaining this library, but Duktape finally hit the 1.0.0 milestone. Theres been a few other releases between the current 1.0.2 and 0.11.0. I'm not sure if you think the library should be incrementally updated for each or not.

I'd love to add Duktape to https://github.com/sstephenson/execjs.