browserify cannot find module babelify

``` bash
$ browserify app.js -o app-built.js
Error: Cannot find module 'babelify' from '/home/rmohr/projects/leaflet/esri-leaflet-browserify-example/node_modules/esri-leaflet-geocoder'
at /usr/local/lib/node_modules/browserify/node_modules/resolve/lib/async.js:46:17
at process (/usr/local/lib/node_modules/browserify/node_modules/resolve/lib/async.js:173:43)
at ondir (/usr/local/lib/node_modules/browserify/node_modules/resolve/lib/async.js:188:17)
at load (/usr/local/lib/node_modules/browserify/node_modules/resolve/lib/async.js:69:43)
at onex (/usr/local/lib/node_modules/browserify/node_modules/resolve/lib/async.js:92:31)
at /usr/local/lib/node_modules/browserify/node_modules/resolve/lib/async.js:22:47
at Object.oncomplete (fs.js:107:15)
```

If I `npm install babelify` and try again I get

```
$ browserify app.js -o app-built.js
ReferenceError: [BABEL] /home/rmohr/projects/leaflet/esri-leaflet-browserify-example/node_modules/esri-leaflet/src/EsriLeaflet.js: Unknown option: base.whitelist while parsing file: /home/rmohr/projects/leaflet/esri-leaflet-browserify-example/node_modules/esri-leaflet/src/EsriLeaflet.js
at Logger.error (/home/rmohr/projects/leaflet/esri-leaflet-browserify-example/node_modules/babelify/node_modules/babel-core/lib/transformation/file/logger.js:41:11)
at OptionManager.mergeOptions (/home/rmohr/projects/leaflet/esri-leaflet-browserify-example/node_modules/babelify/node_modules/babel-core/lib/transformation/file/options/option-manager.js:289:18)
at OptionManager.init (/home/rmohr/projects/leaflet/esri-leaflet-browserify-example/node_modules/babelify/node_modules/babel-core/lib/transformation/file/options/option-manager.js:486:10)
at File.initOptions (/home/rmohr/projects/leaflet/esri-leaflet-browserify-example/node_modules/babelify/node_modules/babel-core/lib/transformation/file/index.js:211:75)
at new File (/home/rmohr/projects/leaflet/esri-leaflet-browserify-example/node_modules/babelify/node_modules/babel-core/lib/transformation/file/index.js:129:22)
at Pipeline.transform (/home/rmohr/projects/leaflet/esri-leaflet-browserify-example/node_modules/babelify/node_modules/babel-core/lib/transformation/pipeline.js:48:16)
at Babelify._flush (/home/rmohr/projects/leaflet/esri-leaflet-browserify-example/node_modules/babelify/index.js:28:24)
at Babelify. (_stream_transform.js:130:12)
at Babelify.g (events.js:180:16)
at Babelify.EventEmitter.emit (events.js:117:20)
```