Only draw intersections for {high,water,rail,aero}way lines

Fixes #1471

js/id/core/node.js

@@ -28,7 +28,11 @@ _.extend(iD.Node.prototype, {
     isIntersection: function(resolver) {
         return resolver.transient(this, 'isIntersection', function() {
             return resolver.parentWays(this).filter(function(parent) {
-                return parent.geometry(resolver) === 'line';
+                return (parent.tags.highway ||
+                    parent.tags.waterway ||
+                    parent.tags.railway ||
+                    parent.tags.aeroway) &&
+                    parent.geometry(resolver) === 'line';
             }).length > 1;
         });
     },

test/spec/core/node.js

@@ -43,6 +43,24 @@ describe('iD.Node', function () {
         });
     });
 
+    describe("#isIntersection", function () {
+        it("returns true for a node shared by more than one highway", function () {
+            var node = iD.Node(),
+                w1 = iD.Way({nodes: [node.id], tags: {highway: 'residential'}}),
+                w2 = iD.Way({nodes: [node.id], tags: {highway: 'residential'}}),
+                graph = iD.Graph([node, w1, w2]);
+            expect(node.isIntersection(graph)).to.equal(true);
+        });
+
+        it("returns true for a node shared by more two non-highways", function () {
+            var node = iD.Node(),
+                w1 = iD.Way({nodes: [node.id]}),
+                w2 = iD.Way({nodes: [node.id]}),
+                graph = iD.Graph([node, w1, w2]);
+            expect(node.isIntersection(graph)).to.equal(false);
+        });
+    });
+
     describe("#asJXON", function () {
         it('converts a node to jxon', function() {
             var node = iD.Node({id: 'n-1', loc: [-77, 38], tags: {amenity: 'cafe'}});