Improvements

Two bugs:

- markers didn't show the right property on click
- search didn't work

After getting familiar with the project I noticed we were trying to access a property called `__gm_id` on markers, and that property didn't exist. I'm not sure when or how that happened. There is a different property on the marker called `closure_uid_NNNNNN` (the number is random), so I refactored to use that as the ID, and things are good.