1) Use arrows <--> to indicate duration
2) Use : to introduce date
3) Move some text around so slightly... First data moved right so we have
full text width for the timeline
* Add graphic showcasing evolution of life
* Add PR Feedback
* Add comment
* Update date format
* Fix small mistakes
* Add pangea, rewrite intro
* Fix citation, improve intro. Thanks alanblue
* Add indicator for full span and months
* Color improvements