Fix prose.io config for blog post yaml frontmatter

…and fix yaml frontmatter in draft post created by prose.io. Note that
there is still an issue with prose.io adding published: false to posts,
which prevents me from previewing them locally
Chore: fix indentation
Add slug (from url) as .page--[slug] class to body

…and remove slug from page article id
Use variables for text color, update $color-text
:lipstick: Optimize tests for accordion demo
:lipstick: Replace groove border w.linear gradient

Safari treats groove as solid; also gives more precision and looks
crisp on retina
Put post date after title in featured section
Add missing .post__date class in recent post list

(Non-featured version)
:lipstick: ids→classes, add full-bleed img support

Includes changes to positioning of site logo to accommodate full-bleed
splash images; also, fix liquid code for loading splash images in post
template
Put post date after post title in post template
Fix JS for oversized and full-bleed images

childNodes[0] no good, because sometimes gets a text node; need to use
firstElementChild; also, simplify and improve the logic, and use
padding not margin (fixes layout for splash images)
More ids→classes, plus simplify home layout
Use color variables, cleanup use of rhythm mixin
:lipstick: Finish CSS→SASS refactor, fixes, tweaks

No more actual SASS in style.sass, removed generic / crappy classes
partial, use modular partials instead
Chore: compiled CSS from latest changes