Add new layer : Landfill, mine/quarry map data via OpenStreetMap

[sagarpreet-chadha]

We are preparing to participate in Google Code-in, and have reserved this issue for participants in GCI - but we'd love to have your help with another one! Please check out https://code.publiclab.org to see more.

We have many layers implemented on this library , see this demo here :
https://publiclab.github.io/leaflet-environmental-layers/example/index.html#3/43.00/-46.23

Lets add a new layer using this API :
[See this issue for more details about API]

We can take help from this merged PR [Comments have been added in this PR where changes are required] :
https://github.com/publiclab/leaflet-environmental-layers/pull/8/files

Happy to help :)

[jywarren]

This was added to the GCI dashboard!

[kevinzluo]

Hello. I have claimed this task on the GCI dashboard. I checked out the JSON output and it appears it doesn't give the lat and lng coordinates for each node id. Though we can get this by making more requests, I feel like it would be better to parse the xml instead. I will try working on this.

Thank you,
Kevin Luo