add a pointzoom feature like the mapbox.js geocoder

[ckc11]

If the geocoder returns a result without a bbox object, the map just centers the map on the result, and if the current zoom level is very low (i.e. zoomed out) then the centering of the map on the search result isn't very helpful. It would be great to implement a minimum zoom level for a point result that does not have an associated bbox.

The mapbox.js library is currently using a pointZoom option of 16.

options: {
        proximity: true,
        position: 'topleft',
        pointZoom: 16,
        keepOpen: false,
        autocomplete: false
    }

and using it in the chooseResult function:

if (result.bbox) {
    this._map.fitBounds(util.lbounds(result.bbox));
} else if (result.center) {
    this._map.setView([result.center[1], result.center[0]], (this._map.getZoom() === undefined) ?
        this.options.pointZoom :
        Math.max(this._map.getZoom(), this.options.pointZoom));
}

so it can be easily added to the change event on the "flyTo" instead of just centering:

input.addEventListener('change', function() {
  var selected = this._typeahead.selected;
  if (selected) {
    if (this.options.flyTo) {
      if (selected.bbox && selected.context <= 3) {
        var bbox = selected.bbox;
        map.fitBounds([[bbox[0], bbox[1]],[bbox[2], bbox[3]]]);
      } else {
        map.flyTo({ center: selected.center });
      }
    }
    this._input = selected;
    this.fire('result', { result: selected });
  }
}.bind(this));

[tristen]

@ckc11 👍 up for putting this together in a pull request?