Documentation needs to be fixed

The Getting Started guide is very misleading right at the beginning of one of the steps: http://alt.js.org/guide/actions/

Apparently, classes are not supported natively and only ES5 style works

This kind of unexpected result may put off some new users

If you run the **exact** code on the webpage (and there's not a whole lot to it), it returns:
```
TypeError: Class constructor LocationActions cannot be invoked without 'new'
at new ActionsGenerator (/node_modules/alt/lib/index.js:187:72)
at Alt.createActions (/node_modules/alt/lib/index.js:211:28)
at Object. (/actions/locations.js:9:22)
at Module._compile (internal/modules/cjs/loader.js:689:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:700:10)
at Module.load (internal/modules/cjs/loader.js:599:32)
at tryModuleLoad (internal/modules/cjs/loader.js:538:12)
at Function.Module._load (internal/modules/cjs/loader.js:530:3)
at Function.Module.runMain (internal/modules/cjs/loader.js:742:12)
at startup (internal/bootstrap/node.js:283:19)
```

It **needs** to say that the ES6 classes **need** to be transpiled into the ES5 format''

Granted that happens automatically in the build tools, but for first-timers, things appear broken (if we run them without transpiling)