Feature/hearing maps images

What kind of tests could I add to the leaflet directive?

Should I use another kind of name for the directive? something like "locationMap", "addLocationMap", "renderLocationMap" ?¿?
I would prefer if we would create an entirely new element e.g. `<location-map></location-map>`

So the directive would then be restricted to `'E'` and the name would be then `'locationMap'` instead of `'leaflet'`.
The html files would then be more clear and then the directive would be agnostic about which map rendering library we are using.
-->
```
return {
  restrict: E,
  replace: true,
  template: '<div id="location"></div>',
  scope: {
    latitude: '@',
    longitude: '@',
    polygon: '@'
  }
};
```