"Unexpected token {", due to processRequest function definition syntax?
Hi! First, thank you so much for this and the client module.  I'm using Node v7.5.0 **edit: correction, seems to be Node v4.8.4, inspecting process.version at runtime** and trying to add them to our Meteor based app and hit an early stumbling block with apollo-upload-server v2.0.4.  I add with `meteor npm install --save apollo-upload-server` and import as per your documentation, but the server fails to start with:

```
W20171013-09:34:07.929(7)? (STDERR) Debugger listening on [::]:45969
W20171013-09:38:24.349(7)? (STDERR) packages/modules.js:19849
W20171013-09:38:24.351(7)? (STDERR) function processRequest(request, { uploadDir } = {}) {
W20171013-09:38:24.353(7)? (STDERR)                                  ^
W20171013-09:38:24.354(7)? (STDERR) 
W20171013-09:38:24.355(7)? (STDERR) SyntaxError: Unexpected token {
W20171013-09:38:24.356(7)? (STDERR)     at Object.exports.runInThisContext (vm.js:53:16)
W20171013-09:38:24.357(7)? (STDERR)     at /home/me/app/.meteor/local/build/programs/server/boot.js:332:30
W20171013-09:38:24.358(7)? (STDERR)     at Array.forEach (native)
```

Setting a breakpoint for where this is being thrown, I see `runInThisContext` is part of the meteor bootstrapping process, and has:

`var func = require('vm').runInThisContext(wrapped, scriptPath, true);`

where `wrapped` is a large block of javascript code containing apollo-upload-server, containing:

```
function processRequest(request, { uploadDir } = {}) {
  // Ensure provided upload directory exists
  if (uploadDir) mkdirp.sync(uploadDir);
```

It looks like the `{ uploadDir } = {}` syntax is causing my node system to throw.  Is this new or in any way nonstandard syntax?  I'm fairly new to the latest es6 language features like destructuring.  Before adding your modules, the es6 style Meteor based server was running fine.