Update npm package

[jimzim]

When you have a moment, could you please update the npm package? It is still referencing aws-swf 3.0 and not 4.0 and errors out when executing: [sudo] npm install -g aws-swf-toolkit

I am very interested in using this toolkit as it does a lot of the heavy lifting for creating deciders and workers. I have been playing with aws-swf, but I think the toolkit will help speed up a lot of dev work. Thanks for your effort on this!

[dreadjr]

In the meantime you can clone the source and do npm link