New JSON gulp plugin

- added json example file
- renamed json template input file

source/data/template.json

@@ -0,0 +1,54 @@
+{
+  "demoadditionallinks": [
+    {
+      "href": "demo/intro.html",
+      "text": "Intro"
+    },
+    {
+      "href": "demo/elements.html",
+      "text": "Elements"
+    },
+    {
+      "href": "demo/examples.html",
+      "text": "Examples"
+    },
+    {
+      "href": "demo/tests.html",
+      "text": "Tests"
+    }
+  ],
+  "demolinks": [
+    {
+      "href": "demo/blank.html",
+      "text": "Blank"
+    },
+    {
+      "href": "demo/maintenance.html",
+      "text": "Maintenance"
+    },
+    {
+      "href": "demo/error/304.html",
+      "text": "304"
+    },
+    {
+      "href": "demo/error/404.html",
+      "text": "404"
+    },
+    {
+      "href": "demo/error/403.html",
+      "text": "403"
+    },
+    {
+      "href": "demo/error/400.html",
+      "text": "400"
+    },
+    {
+      "href": "demo/error/500.html",
+      "text": "500"
+    },
+    {
+      "href": "demo/os.html",
+      "text": "OS"
+    }
+  ]
+}