User location marker doesn't update

[luqmaan]

The user location marker doesn't update as you move.

Also, sometimes it just doesn't show up because of timeouts.

I think we can fix this by adding changing getCurrentPosition to watchPosition here https://github.com/open-austin/austingreenmap/blob/master/client/js/utils/index.js#L13-L17. https://developer.mozilla.org/en-US/docs/Web/API/Geolocation/watchPosition

We may also need to add retries in case it throws an error.

[luqmaan]

Ooh, we may need to figure out HTTPS + GitHub pages at some point. https://sites.google.com/a/chromium.org/dev/Home/chromium-security/deprecating-powerful-features-on-insecure-origins