Merge pull request #188 from timhartmann/master - Thx @timhartmann

Create the source folder after npm install - Solved the issue that most people don´t run "gulp copy-assets" after "npm install" - which results in missing files and a lot of support requests.
Thy @timhartmann for this solution.

package.json

@@ -44,5 +44,8 @@
     "owl.carousel": "^2.2.0",
     "undescores-for-npm": "^1.0.0"
   },
-  "devDependencies": {}
+  "devDependencies": {},
+  "scripts": {
+    "postinstall": "gulp copy-assets"
+  }
 }