Support CoffeeScript on the new `deno` JavaScript engine

This is a feature request to see what is needed to support running CoffeeScript on the new deno js engine (see https://deno.land/).

The original author of node is Ryan Dahl (@ry). After a decade of experience, there are several things that he would do over if he could do it all over again de novo (thus, the name deno). There is an excellent video where he describes the rationale to start from scratch and build a modern, secure JavaScript runtime on V8. The deno engine (analogous to what node is), is a single binary executable written in rust that embeds the V8 engine and supports ES6 modules natively. Package management is also greatly simplified.

The deno engine has native support for additional languages such as TypeScript. It does this by automatically transpiling TypeScript code within an isolate and then feeding the transpiled js to the deno engine. Normal JavaScript is fed directly to the V8 engine. While deno isn't done yet, it would be great to be able to bring the beauty and succinctness of CoffeeScript to deno and this issue is an initial attempt to see what is needed to do so.

What I am requesting is to see if we can add support for CoffeeScript to be supported as a first-class isolate like TypeScript.

@GeoffreyBooth or @jashkenas, is this an ok place to raise the question?