updating some deps

- **mkdirp**@0.5.0 has better error checking
- **coffee-script**@1.8.0 doesn't need to be exact IMO, since it's a dev dep
- **debug** and **growl** should be exact, since they are production deps

I realize **debug** and **growl** are both previously TJ modules, but I really don't think we can be too careful considering how widely-used *this* module is.