added o-date--ready class for conditional styling
Clearer wording of docs
Fixed odd sentence in docs
reinstated imperative demo
Merge branch 'styling-hook' of https://github.com/Financial-Times/o-date into styling-hook

* 'styling-hook' of https://github.com/Financial-Times/o-date:
  Fixed odd sentence in docs
  Clearer wording of docs
removed inconsistencies in class/attribute names
Merge branch 'master' into styling-hook

* master:
  exiting when invalid value is passed in as a date

Conflicts:
	main.js
fixed demos
Merge pull request #20 from Financial-Times/styling-hook

Added o-date--ready class for conditional styling