Sync the build dependencies with upstream

[nschonni]

@delisma ran into an issue running the latest generator with Node 4 because the grunt-sass dependency is still using the old version. The _package.json template should be reviewed and updated where possible.

[LaurentGoderre]

Actually, a lot more than dependencies need to be synced up. The new dist structure needs to be implemented as well

[delisma]

So which node version is recommended in order to run the generator properly?

[LaurentGoderre]

I haven't tested anything past 0.12 so I don't know

[delisma]

Well, seems like node and npm have released new versions. https://nodejs.org/en/blog/release/v5.0.0/