Added vertical nav-bar and some UI tweaks.

Changed to bootstrap-3.
Next step: Fill and create all pages to see how the website will look
like.

Don’t forget:
-To implement databases
-Get some pics to see how the website will look like.
-To check how can we chang the active bar dynamically.
-To implement users login.
-To implement admin page to add elements.
-To implement ability to add more categories on the products side bar.