Leaflet update & Render limit decrease for mobile

I've updated Leaflet based on the current Github.  I've done somewhat limited testing and suspect the draw plugin may require updating but everything else seems to be working fine.

This fixes some issues on mobile.  In particular the double click behavior in Webview is mostly prevented making things like the layer chooser, zoom and pan controls, at least somewhat useable now.

In my testing if the map is failing to render it's likely the user has enabled too many plugins for their device to handle at the zoom level they are trying to view.  In an effort to counteract that issue I've reduced the render limit for the mobile version to half of the defaults.