Rename directories and move image assets to /asset/images/ folder

All images moved to /asset/images
/assets/img > /assets/images
/assets/css > /assets/stylesheets
/assets/js > /assets/javascript
/assets/font > /assets/fonts
Fix missing 'scretch-bar'
Single 's'
Merge pull request #1 from Hengjie/Rename

Rename folders