Create the categories like the presets

The lack of locationSet was causing them to not show up, which indirectly
broke the tutorial at the step where user needs to pick the road category.

modules/presets/category.js

@@ -6,7 +6,7 @@ import { presetCollection } from './collection';
 // `presetCategory` builds a `presetCollection` of member presets,
 // decorated with some extra methods for searching and matching geometry
 //
-export function presetCategory(categoryID, category, all) {
+export function presetCategory(categoryID, category, allPresets) {
   let _this = Object.assign({}, category);   // shallow copy
   let _searchName; // cache
   let _searchNameStripped; // cache
@@ -14,7 +14,7 @@ export function presetCategory(categoryID, category, all) {
   _this.id = categoryID;
 
   _this.members = presetCollection(
-    category.members.map(presetID => all.item(presetID)).filter(Boolean)
+    (category.members || []).map(presetID => allPresets[presetID]).filter(Boolean)
   );
 
   _this.geometry = _this.members.collection

modules/presets/index.js

@@ -136,15 +136,21 @@ export function presetIndex() {
       });
     }
 
-    // Need to rebuild _this.collection before loading categories
-    _this.collection = Object.values(_presets).concat(Object.values(_categories));
-
     // Merge Categories
     if (d.categories) {
       Object.keys(d.categories).forEach(categoryID => {
-        const c = d.categories[categoryID];
+        let c = d.categories[categoryID];
+
         if (c) {   // add or replace
-          _categories[categoryID] = presetCategory(categoryID, c, _this);
+          c = presetCategory(categoryID, c, _presets);
+          if (c.locationSet) {
+            newLocationSets.push(c);
+          } else {
+            c.locationSet = { include: ['Q2'] };  // default worldwide
+            c.locationSetID = '+[Q2]';
+          }
+          _categories[categoryID] = c;
+
         } else {   // remove
           delete _categories[categoryID];
         }

test/spec/presets/category.js

@@ -9,17 +9,17 @@ describe('iD.presetCategory', function() {
     var residential = iD.presetPreset('highway/residential',
         { tags: { highway: 'residential' }, geometry: ['line'] }
     );
-    var all = iD.presetCollection([residential]);
+    var allPresets = { 'highway/residential': residential };
 
 
     it('maps members names to preset instances', function() {
-        var c = iD.presetCategory('road', category, all);
+        var c = iD.presetCategory('road', category, allPresets);
         expect(c.members.collection[0]).to.eql(residential);
     });
 
     describe('#matchGeometry', function() {
         it('matches the type of an entity', function() {
-            var c = iD.presetCategory('road', category, all);
+            var c = iD.presetCategory('road', category, allPresets);
             expect(c.matchGeometry('line')).to.eql(true);
             expect(c.matchGeometry('point')).to.eql(false);
         });