Removed coffe-script register from process container

This is taking a lot of ram and is not useful if you don't run any
coffescript. It is required when the extension name is `.coffee`

We could add an `--interpreter coffee` but atm `cluster` mode does not take any  (https://github.com/Unitech/pm2/blob/master/lib/CLI.js#L87) and it is still running with node, not with coffee so it could mislead users.