Improve HTML lint.

grunt-config/htmllint.js

@@ -1,6 +1,15 @@
 module.exports = {
     frontend: {
-      options: {},
+      options: {
+        'attr-name-style': 'dash',
+        'attr-quote-style': 'double',
+        'attr-req-value': false,
+        'doctype-html5': true,
+        'id-class-ignore-regex': '{{.*?}}',
+        'id-class-style': 'dash',
+        'indent-style': 'spaces',
+        'indent-width': 2
+      },
       src: [
         'accountant/frontend/templates/**/*.html',
         'accountant/frontend/static/templates/**/*.html'