WIP failing feature
Make Organisation model aware of executive office
Basic models
tweaked first failing feature
Rework modelling
Basic CRUD for PromotionalFeature
Adding, editing and deleting feature items
Remove empty template for now
Add image to promotional items
Rename the optional link/title on feature items
Can delete promotional features
Rename PromotionalItem to PromotionalFeatureItem

Makes things more understandable
Add link model
Assignment of a single link via nested attributes
Fix broken controller action
Allow dynamic adding of feature links

I based the JavaScript on the code used to manage contact phone
numbers. The main difference is that I'm setting the nested attribute
destroy attribute on the front-end directly, rather than having
to do it in the controller based on blank inputs.
Rename fixture file
Add flag for double-width feature items
Limit the number of items per-promo feature
Limit the number of links that can be added