Allow treating area as node

[mrmaxguns]

It's important to allow areas the ability to be treated as nodes in order for them to have things like icons and labels. This should be done in the <layers> portion of the stylesheet because it's a display option.

Proposal

<selectors>
  <way id="hospital">
    <or>
      <tag k="amenity" v="hospital"/>
      <tag k="amenity" v="clinic"/>
      <tag k="amenity" v="doctors"/>
    </or>
  </way>
</selectors>
<layers>
  <waytopoint id="hospital">
    <nodeshape vertices="8" radius="0.8mm" fill="#ffb3b3" stroke="#cc6666" thickness="0.2"/>
    <nodeshape vertices="3" radius="0.5mm" fill="#ffffff" thickness="0.2"/>
  </waytopoint>
</layers>

• A new layer called waytopoint that applies to Way geometry
• One or more Node layers
• Internally, the waytopoint layer uses an algorithm to find a suitable node for the given way and then feeds it to the inner layers
• Layers are rendered in order from first to last, as is the case normally

Implementation

Mapbox polylabel is appropriate