Grunt updated with html validation

Changes to node_modules folder:
- Added files for html validation

Changes to root:
- Gruntfile updated for html validation
- package.json updated for html validation
- feedback answer moved to index.html from feedbackanswer.js

changes to JS folder:
- feedbackanswer.js editted -> moved feedback html code to index.html
- showhide.js improved and added show/hide functionality for
feedback-article
Merge pull request #11 from glocom/master

Grunt updated with html validation