mapbox templates

[`__defineGetter__` is old juju](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/__defineGetter__). Use [the `get` operator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/get) instead:

```
function Location() {
  ...
  get lat () {
  },