Close running code tag
Make examples for periods for time more clear
Add xkcd comic
Change to lower case
Move xkcd image to end of presentation
Use 30th of month to loose ambiguity
Use dash instead hyphen
Extras slide!
Merge branch 'master' of github.com:oschrenk/iso8601-presentation

* 'master' of github.com:oschrenk/iso8601-presentation:
  Fix typo