Wandering Cubes - Reduce markup

Every browser that supports CSS animations also supports :before and :after pseudo-elements. So to avoid unnecessary markup we can remove the inner divs and use these elements instead. Pull request follows.
Fix keyframes for fading circle

Fixes #51
Merge pull request #54 from tobiasahlin/fading-circle-keyframe-fix

Fix keyframes for fading circle
Set fill mode through animation shorthand
Use animation shorthand for circle and fading circle
Merge pull request #52 from Fidelix/master

Wandering Cubes - Reduce markup
Short header style
Remove coffeescript fallback implementation
Remove redundant header
Merge pull request #64 from tobiasahlin/clean-up-readme

Clean up readme
Merge pull request #56 from tobiasahlin/use-animation-shorthand

Set fill mode through animation shorthand
Merge with upstream