CHORE: Consider updating node version in package.json and throw away babel dependencies

Hey, 

As it seems to me, you have a strict contract of using an old version of node in your package.json:

``` 
"engines": {
        "node": "0.10.x"
    },
``` 

Furthermore, you seem to use babel-transpiler, which should already shipped with an actual version of node. As a result you maybe could get rid of a lot of babel stuff.

Cheers

Tim.