Live reload not working
**Expected behavior:**

In the styleguide example when running `npm run render` and changing `designSystem.js` the Sketch doc should be updated.

**Observed behavior:**

Running `npm run render` throws the following error and the Sketch doc does not update until you restart Sketch:

```
npm run render

> styleguide@ render /Users/mike/code/react-sketchapp/examples/styleguide
> skpm-build --watch --run

🖨  Copied src/manifest.json in 3ms
/bin/bash: ~/Applications/Sketch.app/Contents/Resources/sketchtool/bin/sketchtool: No such file or directory
Looks like we can't find Sketch.app.\nYou can specify where to look for it by running:\n\necho "sketchPath: ABSOLUTE/PATH/TO/Sketch.app" > ~/.skpmrc
🛠  Built ./main.js in 1248ms
```

**How to reproduce:**

Run `npm install && npm run render` in `react-sketchapp/examples/styleguide`

**Sketch version:**

47.1
