Revert "Update grid - make post text 640px wide (old 630px)"

This reverts commit ec5dfdf954cbbac93c302a1b34785efdd58fe7ac.
Revert single post date style to: 29.augusts, 2014
Update base font size to 18px, dimm down base text color, tweak typography
Update first posts typography
Update grid: make base text width 600px
Add site.url value
Add robots.txt file
Add sitemap
Update post/project footer: add bio info to posts footers
Update project header styles + smaller logo on mobile
Hide menu on mobile when clicked outside .responsive-nav
Remove bottom margin from bio page (because .post-entry adds too much margin for bio page)
Add Grunt. Tasks: cssmin, uglify, browserSync, autoprefixer, watch
Add {{ site.url }} to canonical attribute
Close nav if clicked on body