add HTMLTemplateElement as an available polyfill

.gitignore

@@ -18,4 +18,5 @@ polyfills/WebAnimations/polyfill.js
 polyfills/_TypedArray/polyfill.js
 polyfills/atob/polyfill.js
 polyfills/fetch/polyfill.js
+polyfills/HTMLTemplateElement/polyfill.js
 .nyc_output/

package.json

@@ -45,6 +45,7 @@
   },
   "dependencies": {
     "@financial-times/polyfill-useragent-normaliser": "^1.1.0",
+    "@webcomponents/template": "^1.4.0",
     "Base64": "^1.0.0",
     "audio-context-polyfill": "^1.0.0",
     "diff": "1.4.0",

polyfills/HTMLTemplateElement/config.json

@@ -0,0 +1,32 @@
+{
+  "browsers": {
+    "edge": "<12",
+    "edge_mob": "<12",
+    "ie": "9 - *",
+    "ie_mob": "10 - *",
+    "firefox": "4 - 22",
+    "opera": "10 - 22",
+    "safari": "6 - 9",
+    "chrome": "* - 35",
+    "ios_saf": "* - 9",
+    "firefox_mob": "<67",
+    "bb": "7 - 10",
+    "android": "<67"
+  },
+  "dependencies": [
+    "DocumentFragment",
+    "document.querySelector",
+    "Object.defineProperties",
+    "Object.getOwnPropertyDescriptor",
+    "Object.defineProperty",
+    "Event"
+  ],
+  "license": "BSD-3-Clause",
+  "spec": "https://html.spec.whatwg.org/multipage/scripting.html#the-template-element",
+  "repo": "https://github.com/webcomponents/polyfills/tree/master/packages/template",
+  "docs": "https://developer.mozilla.org/en-US/docs/Web/HTML/Element/template",
+  "install": {
+    "module": "@webcomponents/template",
+    "paths": ["template.js"]
+  }
+}

polyfills/HTMLTemplateElement/detect.js

@@ -0,0 +1 @@
+'HTMLTemplateElement' in this