Add the 'current location' button

[mvysny]

The web Google Maps has this "crosshair" current location button available, please see screenshot for more details. Would it be possible to add an API to show the button?

[mvysny]

Looks like it's not baked in the Google Maps JavaScript API:

1. The initial demo of the component at https://developers.google.com/maps/documentation/javascript/overview doesn't show the crosshair button
2. There's a documentation to add the "Current location" button here: https://developers.google.com/maps/documentation/javascript/geolocation

[mvysny]

This is reported upstream, with unfortunately no activity since 2017: https://issuetracker.google.com/issues/35829640

[mvysny]

See solution in #115

[javier-godoy]

Hello. With support for the Controls API (#115), the current location button would be just an example on how to call goToCurrentLocation from a custom control, and we should update the geolocation example in demo so that it uses the new API.

We'll keep this issue open until #115 is resolved.