Issue #8: Debloat Library

[jcar787]

Using lodash.get, lodash.last and lodash.sortby instead of the whole loadash library.
Dist files:

• iron-db.min.js - before: 75.2 kb | after: 23.6 kb
• iron-db.js - before: 545 kb | after: 113 kb

Also added webpack-dev-server as a devDependency.
npm run serve should open a server and display the contents. Easier for testing.

[jcar787]

Fixes
https://github.com/gruns/irondb/issues/8

[guanzo]

It's easier to use lodash-es, which allows for tree shaking. Not sure if lodash-es would result in a smaller bundle than individual imports.

[jcar787]

Sadly is not gonna result in small bundle, it's gonna be pretty much the same as importing lodash entirely. That's why I prefer just importing the functions that were used already.

[gruns]

It's easier to use lodash-es, which allows for tree shaking. Not sure if
lodash-es would result in a smaller bundle than individual imports.

Turns out, lodash-es indeed results in a smaller bundle than both lodash
(duh) and lodash.get + lodash.last + lodash.sortby.

Results of npm run build with

• lodash: 76986 byte iron-db.min.js
• lodash.get, lodash.last, and lodash.sortby: 24161 byte iron-db.min.js
• lodash-es: 23753 byte iron-db.min.js

Winner: lodash-es. I switched to such in 974402a.

Huge thank you for your PR and input, @jcar787 and @guanzo. Don't hesitate to
let me know if there's anything else I can do for you.