Interesting. Their 200 dollar tier is basically my 'all backers' tier (name in a readme file). But I can probably come up with something slightly more valuable to offer at ~250€.
As for CoffeeScript support -- the only major piece missing there is an error-tolerant CoffeeScript parser. Given that, one could simply run the CoffeeScript compiler over code, and analyze the output. There'd be some shuffling with source maps needed to translate source locations in the various representations of the code, but that's a solved problem. Well, and of course you might see some translation artifacts. The CS output code is semantically close to the input, but there are differences.
As for CoffeeScript support -- the only major piece missing there is an error-tolerant CoffeeScript parser. Given that, one could simply run the CoffeeScript compiler over code, and analyze the output. There'd be some shuffling with source maps needed to translate source locations in the various representations of the code, but that's a solved problem. Well, and of course you might see some translation artifacts. The CS output code is semantically close to the input, but there are differences.