Deduped modules don't get included in worker blob

This causes an exception at runtime when the missing module is required.

The `resolveSources` function tries to recursively find all dependencies, but it doesn't know about modules that are deduped, which have an entry in the modules map that looks like this:

```js
"/Users/jhiesey/Projects/node/stream-http/node_modules/inherits/inherits_browser.js": [function(require, module, exports) {
arguments[4]["/Users/jhiesey/Projects/node/airtap/node_modules/inherits/inherits_browser.js"][0].apply(exports, arguments)
}
, {}]
```

The module the dedupe entry points to ("/Users/jhiesey/Projects/node/airtap/node_modules/inherits/inherits_browser.js") needs to be included too, but `resovleSources` doesn't know that, so the dedupe entry throws at runtime.