Render circular place=* as an unfilled area

Basically, give it area label placement, but line
behavior otherwise.

Test case: #id=w169604918&map=19.46/41.41402/-70.94773

css/map.css

@@ -359,6 +359,7 @@ path.fill.tag-amenity-parking {
     fill: #aaa;
 }
 
+path.fill.tag-place,
 path.fill.tag-boundary {
     fill: none;
 }

js/id/core/way.js

@@ -161,5 +161,6 @@ iD.Way.areaKeys = {
     amenity: {},
     shop: {},
     man_made: {},
-    public_transport: {}
+    public_transport: {},
+    place: {}
 };

js/id/svg/tag_classes.js

@@ -2,7 +2,7 @@ iD.svg.TagClasses = function() {
     var keys = iD.util.trueObj([
         'highway', 'railway', 'waterway', 'power', 'motorway', 'amenity',
         'natural', 'landuse', 'building', 'oneway', 'bridge', 'boundary',
-        'leisure', 'construction'
+        'leisure', 'construction', 'place'
     ]), tagClassRe = /^tag-/,
         tags = function(entity) { return entity.tags; };