More personal and professional info in the page

Took material away from the Fatiando page and added here.
Made page for software and publications.
Added picture to about page. Removed social links from menu bar.
Style tweaks

Darker green for links and nav, bold for nav items, grey background for
code elements, sans-serif font
Reduced pic quality and added mention of pinga

Added the logo and a little text in the About page
Added education and latest talks to about page
Mention Software Carpentry in Software page
Merge pull request #4 from leouieda/more-info-pages

Filled the page with more information about me