ES module output

[g-ortuno]

I might be holding it wrong but I can't find a way to generate plain ES6 modules. I can only generate code with good.module(). Using "module": "es6" causes an error.

[mprobst]

TsickleHost has an option googmodule that you can set to false, but its only exposed through the programmatic API.

Beware though, we've never tested tsickle together with Closure's ES module support. There are several areas where things might break (e.g. referring to names from externs etc).