I like that the default for all modules is `false` (although I think custom could probably default to false too), but then you add the flags to turn them all on in the default task. What would be nice is an additional rake task (or optional arguments to this one) that turn on support for selective modules only, as I think the other common use case will be generating a custom webfont.js that only supports 1-2 providers. A rake task for that + some documentation added to the `README.md` would be excellent.