Lock down CS version to 1.6.x

Any chance we can lock down the CoffeeScript version? Or at least have a separate npm version for a locked down version to 1.6.x?

We're not ready to move to CS 1.7 yet - and there are some breaking changes preventing us from doing so - but coffeelint will automatically install 1.7 anyway, and there's no option to stop this.

AFAICT coffeelint works with 1.7 - but without a separate npm version/branch there's no way to specify it to use 1.6