Adding a lot of stuff for optimizing portfolio data management and more.

I've made some changes.
First of all I've transfer the site data into a dedicated document where you can manage all the contents into the page (based on [jekyll data files] (http://jekyllrb.com/docs/datafiles/) ).
Then I've removed inline style, for background-image, adding variables that can be parsed by jekyll in the main.scss file which is the only one where you can add liquid syntax.
Then into portfolio.yml data file, now you can create your custom menu list and url link associated to the item plus a list for the skills where a user can add or remove data without editing code, well at least not HTML. 

Hope you enjoy!