Add the option to only show items with particular capabilities

dev/config.js

@@ -13,6 +13,17 @@ module.exports = [
     "defaultValue": "Some arbitrary text explaining how this all works. " +
              "It's cool if this wraps across multiple lines"
   },
+  {
+    "type": "section",
+    "capabilities": ["RECT", "MICROPHONE"],
+    "items": [
+      {
+        "type": "text",
+        "defaultValue": "This section is only visible for rectangular devices that" +
+                        " have a microphone"
+      }
+    ]
+  },
   {
     "type": "section",
     "items": [
@@ -20,6 +31,11 @@ module.exports = [
         "type": "heading",
         "defaultValue": "This is a section"
       },
+      {
+        "type": "text",
+        "defaultValue": "This is only visible for aplite",
+        "capabilities": ["APLITE"]
+      },
       {
         "type": "input",
         "appKey": "email",