Deployment improvements (auto purge cache etc)

package.json

@@ -32,7 +32,8 @@
     "scripts": {
         "build": "gulp build",
         "lint": "eslint src/js && npm run-script remark",
-        "remark": "remark -f --use 'validate-links=repository:\"sampotts/plyr\"' '{,!(node_modules),.?**/}*.md'",
+        "remark":
+            "remark -f --use 'validate-links=repository:\"sampotts/plyr\"' '{,!(node_modules),.?**/}*.md'",
         "test": "echo \"Error: no test specified\" && exit 1"
     },
     "devDependencies": {
@@ -45,6 +46,7 @@
         "eslint-config-airbnb-base": "^13.0.0",
         "eslint-config-prettier": "^2.9.0",
         "eslint-plugin-import": "^2.13.0",
+        "fastly-purge": "^1.0.1",
         "git-branch": "^2.0.1",
         "gulp": "^3.9.1",
         "gulp-autoprefixer": "^5.0.0",
@@ -80,7 +82,8 @@
         "stylelint-config-sass-guidelines": "^5.0.0",
         "stylelint-order": "^0.8.1",
         "stylelint-scss": "^3.1.3",
-        "stylelint-selector-bem-pattern": "^2.0.0"
+        "stylelint-selector-bem-pattern": "^2.0.0",
+        "through2": "^2.0.3"
     },
     "dependencies": {
         "babel-polyfill": "^6.26.0",