Use lodash babel plugin for UMD build

[saminzadeh]

This PR utilizes the babel lodash plugin to automatically cherry-pick Lodash modules.

This has a few advantages:

• Don't need to figure out which modules you are using, they will be automatically determined at build time
• Projects that include your package via NPM can have their own build system include lodash and resolve dependencies.

Benchmarks (minified is about the same 😄 )

Before Plugin:

File sizes after gzip:

umd/itemsjs.js 26.41 KB
umd/itemsjs.min.js 14.52 KB

After Plugin:

File sizes after gzip:

umd/itemsjs.js 45.37 KB
umd/itemsjs.min.js 14.53 KB

[saminzadeh]

Will revisit once we get UMD builds configured on all envs